From 8000633519a1445f83371d5db181e4f617021136 Mon Sep 17 00:00:00 2001 From: Bissbert <43237892+Bissbert@users.noreply.github.com> Date: Tue, 5 May 2026 19:18:49 +0700 Subject: [PATCH] style(lang): British English compliance and AI-tell removal across learn content MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Replace all prose em-dashes (—) with Oxford-style spaced en-dashes ( – ); 26 residual em-dashes retained as legitimate null table-cell markers ("—") - AmE → BrE: traveling → travelling (optical-properties.yaml) - Remove AI-tell phrases: "in today's market/gem market" rephrased in pearl.yaml, burma/ruby.yaml, and east-africa/tsavorite.yaml - Fix six line-break instances where em-dash replacement created leading – on a new line (twin-laws, ethiopia, montana-sapphire, russia/demantoid, thailand/ruby, thailand/overview) - Protect citation titles, author names, proper nouns, chemical formulas, and YAML keys - YAML parse confirmed clean across all 138 files Co-Authored-By: Claude Sonnet 4.6 --- docs/learn/care/gem-care-durability.yaml | 4 +- .../equipment/advanced-lab-instruments.yaml | 28 +++--- .../equipment/chelsea-colour-filter.yaml | 42 ++++----- docs/learn/equipment/conoscope.yaml | 26 +++--- docs/learn/equipment/diamond-screening.yaml | 46 +++++----- docs/learn/equipment/dichroscope.yaml | 8 +- docs/learn/equipment/other-tools.yaml | 14 +-- docs/learn/equipment/overview.yaml | 2 +- docs/learn/equipment/polariscope.yaml | 2 +- docs/learn/equipment/refractometer.yaml | 16 ++-- docs/learn/equipment/sg-measurement.yaml | 46 +++++----- docs/learn/equipment/spectroscope.yaml | 66 +++++++------- docs/learn/equipment/uv-lamp.yaml | 2 +- .../fundamentals/chemical-properties.yaml | 14 +-- docs/learn/fundamentals/colour-theory.yaml | 76 ++++++++-------- docs/learn/fundamentals/crystal-systems.yaml | 32 +++---- .../crystallography-advanced.yaml | 2 +- .../optic-sign-determination.yaml | 22 ++--- .../fundamentals/optical-properties.yaml | 10 +-- .../fundamentals/physical-properties.yaml | 44 +++++----- docs/learn/fundamentals/twin-laws.yaml | 54 ++++++------ .../treatments-deep/beryllium-diffusion.yaml | 14 +-- .../treatments-deep/cvd-diamond.yaml | 18 ++-- .../treatments-deep/hpht-diamond.yaml | 14 +-- .../treatments-deep/lead-glass-ruby.yaml | 20 ++--- docs/learn/identification/treatments.yaml | 88 +++++++++---------- docs/learn/market/grading-valuation.yaml | 2 +- docs/learn/origin/afghanistan/emerald.yaml | 14 +-- docs/learn/origin/afghanistan/lapis.yaml | 16 ++-- docs/learn/origin/afghanistan/overview.yaml | 14 +-- docs/learn/origin/brazil-additional.yaml | 18 ++-- docs/learn/origin/burma/ruby.yaml | 2 +- docs/learn/origin/cambodia.yaml | 18 ++-- docs/learn/origin/ceylon.yaml | 2 +- docs/learn/origin/colombia-mines.yaml | 32 +++---- docs/learn/origin/colombia.yaml | 2 +- docs/learn/origin/east-africa/tsavorite.yaml | 2 +- docs/learn/origin/ethiopia.yaml | 36 ++++---- docs/learn/origin/india.yaml | 22 ++--- docs/learn/origin/iran.yaml | 18 ++-- docs/learn/origin/mozambique.yaml | 26 +++--- docs/learn/origin/pakistan/emerald.yaml | 10 +-- docs/learn/origin/pakistan/overview.yaml | 14 +-- docs/learn/origin/pakistan/ruby.yaml | 14 +-- docs/learn/origin/pakistan/topaz.yaml | 8 +- docs/learn/origin/russia/alexandrite.yaml | 16 ++-- docs/learn/origin/russia/demantoid.yaml | 36 ++++---- docs/learn/origin/russia/emerald.yaml | 8 +- docs/learn/origin/russia/overview.yaml | 16 ++-- docs/learn/origin/tajikistan.yaml | 14 +-- docs/learn/origin/thailand/overview.yaml | 8 +- docs/learn/origin/thailand/ruby.yaml | 12 +-- docs/learn/origin/thailand/sapphire.yaml | 8 +- docs/learn/origin/thailand/zircon.yaml | 8 +- docs/learn/origin/usa/montana-sapphire.yaml | 22 ++--- docs/learn/origin/usa/overview.yaml | 18 ++-- docs/learn/origin/usa/utah-red-beryl.yaml | 20 ++--- docs/learn/origin/vietnam.yaml | 20 ++--- docs/learn/origin/zimbabwe.yaml | 30 +++---- docs/learn/phenomena/alexandrite-effect.yaml | 26 +++--- docs/learn/phenomena/aventurescence.yaml | 2 +- docs/learn/phenomena/colour-change.yaml | 4 +- docs/learn/phenomena/fire-dispersion.yaml | 20 ++--- docs/learn/phenomena/fluorescence.yaml | 44 +++++----- docs/learn/phenomena/iridescence.yaml | 2 +- docs/learn/phenomena/orient.yaml | 22 ++--- docs/learn/phenomena/play-of-colour.yaml | 2 +- docs/learn/phenomena/schiller.yaml | 12 +-- docs/learn/phenomena/silk-effect.yaml | 16 ++-- docs/learn/phenomena/tenebrescence.yaml | 38 ++++---- docs/learn/species/amphibole.yaml | 4 +- docs/learn/species/beryl.yaml | 2 +- docs/learn/species/chrysoberyl.yaml | 2 +- docs/learn/species/feldspar.yaml | 6 +- docs/learn/species/garnet.yaml | 2 +- docs/learn/species/olivine.yaml | 4 +- docs/learn/species/opal.yaml | 6 +- docs/learn/species/pearl.yaml | 2 +- docs/learn/species/pyroxene.yaml | 4 +- docs/learn/species/quartz.yaml | 4 +- docs/learn/species/spinel.yaml | 8 +- docs/learn/species/tourmaline.yaml | 2 +- docs/learn/species/zircon.yaml | 2 +- docs/learn/species/zoisite.yaml | 4 +- 84 files changed, 728 insertions(+), 728 deletions(-) diff --git a/docs/learn/care/gem-care-durability.yaml b/docs/learn/care/gem-care-durability.yaml index a5aafdb..cc4428c 100644 --- a/docs/learn/care/gem-care-durability.yaml +++ b/docs/learn/care/gem-care-durability.yaml @@ -53,7 +53,7 @@ sections: - title: Hardness Considerations content: | - The Mohs scale is ordinal, not linear—the jump from 9 to 10 is enormous. Household + The Mohs scale is ordinal, not linear – the jump from 9 to 10 is enormous. Household dust contains quartz particles (H 7), so gems below 7 will gradually accumulate scratches during normal wear. table: @@ -72,7 +72,7 @@ sections: - title: Toughness and Cleavage content: | - Cleavage—the tendency to break along crystallographic planes—significantly affects + Cleavage – the tendency to break along crystallographic planes – significantly affects toughness. Even hard gems can be brittle. subsections: - title: High-Risk Cleavage Gems diff --git a/docs/learn/equipment/advanced-lab-instruments.yaml b/docs/learn/equipment/advanced-lab-instruments.yaml index e69e47c..ac99b58 100644 --- a/docs/learn/equipment/advanced-lab-instruments.yaml +++ b/docs/learn/equipment/advanced-lab-instruments.yaml @@ -1,5 +1,5 @@ title: Advanced Laboratory Instruments -description: Diploma-level awareness of FTIR, UV-Vis-NIR, Raman, EDXRF, LA-ICP-MS, and photoluminescence spectroscopy — what each detects and its key gemmological applications. +description: Diploma-level awareness of FTIR, UV-Vis-NIR, Raman, EDXRF, LA-ICP-MS, and photoluminescence spectroscopy – what each detects and its key gemmological applications. order: 12 category: equipment difficulty: advanced @@ -33,7 +33,7 @@ sections: - title: FTIR Spectroscopy content: | **Fourier Transform Infrared (FTIR) spectroscopy** irradiates the sample with a broadband - infrared beam — mid-IR (~4000–400 cm⁻¹) or near-IR (~10000–4000 cm⁻¹). Chemical bonds + infrared beam – mid-IR (~4000–400 cm⁻¹) or near-IR (~10000–4000 cm⁻¹). Chemical bonds absorb IR radiation at characteristic frequencies; the resulting absorption pattern identifies molecular functional groups and crystal lattice vibrations. @@ -54,11 +54,11 @@ sections: untreated (Type A) jadeite. Tan et al. (2013) confirmed FTIR distinguishes treated from untreated jade: COSMOS journal (DOI: 10.1142/s0219607713500031) [VERIFIED]. - - **Diamond type classification:** FTIR distinguishes Type Ia (nitrogen in aggregates — + - **Diamond type classification:** FTIR distinguishes Type Ia (nitrogen in aggregates – A and B centres), Type Ib (isolated nitrogen), Type IIa (nitrogen-free), and Type IIb (boron-bearing, electrically conductive) by nitrogen absorption features in the mid-IR one-phonon region (~1000–1300 cm⁻¹). Type IIa diamonds lack nitrogen absorptions and - are more likely candidates for HPHT treatment or CVD synthesis — triggering further + are more likely candidates for HPHT treatment or CVD synthesis – triggering further investigation. - **Heat treatment indicator in sapphire:** Delaunay (2024) showed that the 3232 cm⁻¹ @@ -85,11 +85,11 @@ sections: - title: Key Gemmological Applications content: | - **Beryllium-diffused sapphire detection:** Emmett et al. (2003) described UV-Vis-NIR - signatures associated with beryllium diffusion — the process causes orange colouration + signatures associated with beryllium diffusion – the process causes orange colouration in corundum through Fe³⁺–O²⁻ charge transfer bands in the UV, producing a reduction in blue absorption and strengthening of an absorption feature near 390 nm: Gems & Gemology 39(2), 84–135 (DOI: 10.5741/gems.39.2.84) [VERIFIED]. Be diffusion is - confirmed definitively only by LA-ICP-MS (see below) — UV-Vis-NIR provides supporting + confirmed definitively only by LA-ICP-MS (see below) – UV-Vis-NIR provides supporting evidence. - **Chromophore quantification:** Distinguishes iron-coloured from chromium-coloured @@ -114,7 +114,7 @@ sections: molecular bond vibrations and lattice phonon modes, providing a unique molecular fingerprint. Raman is **non-destructive** and can be performed through glass or immersion media using a - confocal micro-probe — making it ideal for inclusion identification without opening cavities + confocal micro-probe – making it ideal for inclusion identification without opening cavities or damaging the host. subsections: - title: Key Gemmological Applications @@ -151,7 +151,7 @@ sections: and **treatment detection**. They are the workhorses of modern origin determination at major gem laboratories. subsections: - - title: EDXRF — Non-Destructive Elemental Survey + - title: EDXRF – Non-Destructive Elemental Survey content: | **Energy-Dispersive X-ray Fluorescence (EDXRF):** An X-ray beam causes emission of characteristic secondary X-rays from elements in the sample, providing non-destructive @@ -159,17 +159,17 @@ sections: - Non-destructive; no sample preparation required. - Cannot detect elements below atomic number ~11 in standard configurations. - - **Cannot detect beryllium (atomic number 4)** — this is a critical limitation for + - **Cannot detect beryllium (atomic number 4)** – this is a critical limitation for Be-diffusion treatment detection; only LA-ICP-MS can routinely detect Be. - Schmetzer et al. (2009) used EDXRF for gem corundum origin fingerprinting: Gems & Gemology 45(4), 264 (DOI: 10.5741/gems.45.4.264) [VERIFIED]. - - title: LA-ICP-MS — Ultra-Trace Element Fingerprinting + - title: LA-ICP-MS – Ultra-Trace Element Fingerprinting content: | **Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS):** A laser micro-beam ablates a tiny spot (10–100 µm); the ablated material is carried into an ICP plasma and analysed by mass spectrometry, providing trace and ultra-trace element data - to ppb levels. Micro-destructive — leaves a tiny ablation pit. + to ppb levels. Micro-destructive – leaves a tiny ablation pit. - **Origin fingerprinting in corundum:** Basaltic-origin sapphires (Australia, Thailand/Cambodia, Nigeria) have high Fe (>5000 ppm), high Ga/Al ratios, and are @@ -188,7 +188,7 @@ sections: text: | EDXRF: £15,000–£100,000. LA-ICP-MS: £150,000–£500,000. Origin determination using these techniques is performed primarily by GIA, Gübelin, SSEF, and the Gem-A Laboratory. Neither - instrument provides geographic origin assignment alone — statistical comparison against a + instrument provides geographic origin assignment alone – statistical comparison against a reference database of stones of known provenance is required. - title: Photoluminescence at 77 K @@ -210,7 +210,7 @@ sections: Related Materials 19(10), 1254–1258 (DOI: 10.1016/j.diamond.2010.06.007) [VERIFIED]. - **CVD synthetic diamond:** Willems et al. (2011) explored luminescent regions in CVD - synthetic diamond using PL — CVD diamonds show characteristically different luminescence + synthetic diamond using PL – CVD diamonds show characteristically different luminescence patterns related to their growth sectors: Gems & Gemology 47(3), 202–207 (DOI: 10.5741/gems.47.3.202) [VERIFIED]. @@ -225,7 +225,7 @@ sections: Photoluminescence at 77 K requires liquid nitrogen and a purpose-built cryogenic stage, costing £50,000–£200,000. This technique is not available outside major gem laboratories (GIA, Gübelin, SSEF, Gem-A Laboratory). Results require expert interpretation and - comparison against reference databases. Not applicable to most coloured stones — it is + comparison against reference databases. Not applicable to most coloured stones – it is primarily a diamond tool. - title: Sources diff --git a/docs/learn/equipment/chelsea-colour-filter.yaml b/docs/learn/equipment/chelsea-colour-filter.yaml index 2fa74ef..333021e 100644 --- a/docs/learn/equipment/chelsea-colour-filter.yaml +++ b/docs/learn/equipment/chelsea-colour-filter.yaml @@ -1,5 +1,5 @@ title: Chelsea Colour Filter -description: Using the Chelsea Colour Filter as a chromium discriminator for gem identification — including the species reaction table, lighting requirements, and diagnostic limitations. +description: Using the Chelsea Colour Filter as a chromium discriminator for gem identification – including the species reaction table, lighting requirements, and diagnostic limitations. order: 9 category: equipment difficulty: beginner @@ -27,9 +27,9 @@ sections: content: | The CCF is a composite filter containing two glass elements: - - **Didymium glass** — absorbs the mid-green and yellow-green region (~540–580 nm), removing + - **Didymium glass** – absorbs the mid-green and yellow-green region (~540–580 nm), removing the wavelengths that would otherwise appear as a green wash. - - **Cobalt-blue glass** — absorbs red and part of the blue-green region. + - **Cobalt-blue glass** – absorbs red and part of the blue-green region. The combined result leaves two narrow transmission windows: 1. ~570–580 nm (yellow-green) @@ -46,7 +46,7 @@ sections: - title: How to Use the Filter content: | - Correct procedure is essential — the wrong light source gives unreliable results. + Correct procedure is essential – the wrong light source gives unreliable results. subsections: - title: Lighting Requirements content: | @@ -60,11 +60,11 @@ sections: - title: Observation Procedure content: | 1. Hold the filter close to the eye (as close as comfortable). - 2. Hold the stone close to — but not touching — the incandescent light source, + 2. Hold the stone close to – but not touching – the incandescent light source, or direct a penlight through or against the stone. 3. Observe the colour and record as one of: strong red / weak red / pink / inert / weak greenish / green. - 4. Always cross-reference with RI and spectroscope data — the CCF result alone is + 4. Always cross-reference with RI and spectroscope data – the CCF result alone is never diagnostic. - title: Species Reactions @@ -73,7 +73,7 @@ sections: standard incandescent illumination. Anomalous results require immediate investigation with a second instrument. - Note: **the CCF does not distinguish natural from synthetic** — a chromium-dominated + Note: **the CCF does not distinguish natural from synthetic** – a chromium-dominated synthetic will react identically to a natural stone of the same chromophore. table: caption: Chelsea Colour Filter Reaction by Species @@ -84,21 +84,21 @@ sections: - Diagnostic Strength - Notes rows: - - ["Emerald — Colombian / Brazilian (natural)", "Strong red", "Cr³⁺", "High", "High Cr; classic positive reaction"] - - ["Emerald — Zambian (natural)", "Weak red to inert", "Cr³⁺ + Fe", "Moderate", "Elevated Fe suppresses red; less reliable positive"] - - ["Emerald — flux-grown synthetic (Chatham, Gilson)", "Strong red", "Cr³⁺", "High", "High-purity Cr; often stronger than many naturals"] - - ["Emerald — hydrothermal synthetic (Biron, Tairus)", "Strong red", "Cr³⁺", "High", "Same chromophore; indistinguishable from Cr-rich natural"] + - ["Emerald – Colombian / Brazilian (natural)", "Strong red", "Cr³⁺", "High", "High Cr; classic positive reaction"] + - ["Emerald – Zambian (natural)", "Weak red to inert", "Cr³⁺ + Fe", "Moderate", "Elevated Fe suppresses red; less reliable positive"] + - ["Emerald – flux-grown synthetic (Chatham, Gilson)", "Strong red", "Cr³⁺", "High", "High-purity Cr; often stronger than many naturals"] + - ["Emerald – hydrothermal synthetic (Biron, Tairus)", "Strong red", "Cr³⁺", "High", "Same chromophore; indistinguishable from Cr-rich natural"] - ["Aquamarine", "Inert / weak greenish", "Fe²⁺/Fe³⁺", "High", "No significant Cr"] - ["Blue sapphire (natural)", "Greenish / inert", "Fe²⁺–Ti⁴⁺ CT", "High", "No Cr; Fe–Ti charge transfer colouring"] - ["Blue spinel (natural)", "Greenish / inert", "Fe", "High", "Fe-coloured; no Cr"] - - ["Blue spinel (Verneuil synthetic, cobalt-coloured)", "Red", "Co", "Highest", "Cobalt transmits red window strongly — diagnostic for synthetic cobalt spinel"] + - ["Blue spinel (Verneuil synthetic, cobalt-coloured)", "Red", "Co", "Highest", "Cobalt transmits red window strongly – diagnostic for synthetic cobalt spinel"] - ["Blue glass (cobalt-coloured)", "Red", "Co", "Highest", "Same cobalt transmission; separates from blue sapphire"] - ["Green tourmaline (Fe/Mn dominant)", "Greenish / inert", "Fe/Mn", "High", "No significant Cr"] - ["Chrome tourmaline", "Red", "Cr³⁺", "High", "Strong positive; resembles emerald reaction"] - ["Tsavorite (V³⁺/Cr³⁺ grossular)", "Inert to weak greenish", "V³⁺", "Moderate", "V³⁺ absorption differs from Cr³⁺; often inert"] - ["Demantoid garnet (Cr-bearing, Russian)", "Red", "Cr³⁺", "High", "Cr³⁺ colouring in most demantoid"] - - ["Jadeite — natural green (Cr-coloured, imperial)", "Weak greenish to inert", "Cr³⁺", "Low–moderate", "Lower Cr content than emerald; often borderline"] - - ["Jadeite — dyed green (Type C)", "Red", "Organic dye", "High", "Dye absorbs in yellow-green window; red transmission is diagnostic for dyed jade"] + - ["Jadeite – natural green (Cr-coloured, imperial)", "Weak greenish to inert", "Cr³⁺", "Low–moderate", "Lower Cr content than emerald; often borderline"] + - ["Jadeite – dyed green (Type C)", "Red", "Organic dye", "High", "Dye absorbs in yellow-green window; red transmission is diagnostic for dyed jade"] - ["Cobalt glass-filled sapphire", "Strong red", "Co (filler)", "High", "Bexfield 2020 reported this as a new diagnostic technique for detecting cobalt-glass filling (DOI: 10.15506/jog.2020.37.4.357)"] - title: Vanadium-Coloured Stones @@ -106,26 +106,26 @@ sections: type: warning title: Vanadium (V³⁺) Does Not React Like Chromium text: | - Some stones coloured by vanadium (V³⁺) — including many Brazilian emeralds and certain - hydrothermal synthetic emeralds — may give a **weak or inert** reaction under the CCF. + Some stones coloured by vanadium (V³⁺) – including many Brazilian emeralds and certain + hydrothermal synthetic emeralds – may give a **weak or inert** reaction under the CCF. This is because V³⁺ absorption bands differ from Cr³⁺ and do not match the CCF's transmission windows in the same way. - A weak or inert reaction from a green stone does **not** rule out emerald — it may + A weak or inert reaction from a green stone does **not** rule out emerald – it may simply indicate vanadium rather than chromium colouring. Confirm with the spectroscope. - title: Limitations content: | The CCF has important limitations that must be understood before relying on a result: - - **Incandescent light only** — daylight or LED sources shift the colour balance and can + - **Incandescent light only** – daylight or LED sources shift the colour balance and can produce false inert reactions on moderately Cr-coloured stones. - - **Does not distinguish natural from synthetic** — both react red if Cr is the chromophore. + - **Does not distinguish natural from synthetic** – both react red if Cr is the chromophore. Anderson (1966) stated this explicitly; it remains the most commonly misunderstood aspect of the instrument. - **Modern Cr-doped hydrothermal synthetics** (Biron, Tairus) may give reactions indistinguishable from high-quality Colombian naturals. - - **Vanadium-coloured emeralds** may give a weaker or inert reaction — not all green beryl + - **Vanadium-coloured emeralds** may give a weaker or inert reaction – not all green beryl that is called "emerald" is Cr-dominated. - **Low-quality lighting** (fluorescent strip) degrades result reliability; repeat under tungsten if ambiguous. @@ -144,4 +144,4 @@ sections: - Read, P. G. (ed.). *Gems* 7th ed., chapter "The hand lens, microscope and Chelsea filter." DOI: 10.4324/9780080507224-18 [VERIFIED] - Nassau, K. (2001). *The Physics and Chemistry of Color* (2nd ed.). Wiley. - ISBN: 978-0-471-39106-7 [PARTIALLY_SUPPORTED — ISBN only, no DOI] + ISBN: 978-0-471-39106-7 [PARTIALLY_SUPPORTED – ISBN only, no DOI] diff --git a/docs/learn/equipment/conoscope.yaml b/docs/learn/equipment/conoscope.yaml index bc68534..6b227ff 100644 --- a/docs/learn/equipment/conoscope.yaml +++ b/docs/learn/equipment/conoscope.yaml @@ -1,5 +1,5 @@ title: Conoscopic Observation and Interference Figures -description: Using convergent polarised light to observe interference figures that reveal a gemstone's optic character (uniaxial or biaxial) and optic sign — an advanced polariscope technique. +description: Using convergent polarised light to observe interference figures that reveal a gemstone's optic character (uniaxial or biaxial) and optic sign – an advanced polariscope technique. order: 11 category: equipment difficulty: advanced @@ -18,7 +18,7 @@ tags: sections: - title: Introduction content: | - The conoscope converts the polariscope into a device for examining **interference figures** — + The conoscope converts the polariscope into a device for examining **interference figures** – patterns produced by convergent polarised light passing through an anisotropic gemstone. These figures reveal whether a stone is uniaxial or biaxial and, with an accessory plate, allow determination of the optic sign. @@ -34,14 +34,14 @@ sections: subsections: - title: Polariscope vs Conoscope vs Bertrand Lens content: | - - **Polariscope (orthoscopic mode):** Standard test — parallel polarised light; stone + - **Polariscope (orthoscopic mode):** Standard test – parallel polarised light; stone rotated to identify SR, DR, or ADR behaviour. Does not show interference figures. - **Conoscope (convergent mode):** Converging lens added above or below the stone to bring a strongly convergent cone of polarised light to focus within the gem. The resulting interference figure is observed through a Bertrand lens or hand lens above the analyser. - **Bertrand lens:** A small supplementary lens inserted above the analyser that focuses - the back focal plane of the objective or converging lens — making the interference + the back focal plane of the objective or converging lens – making the interference figure visible and centred. - title: Improvised Setup @@ -51,7 +51,7 @@ sections: simple converging element. This improvised setup is described in standard Gem-A teaching materials for use when a conoscope attachment is not available. Note: this improvised method is widely described in gemmological teaching but a specific peer-reviewed paper - confirming its parameters was not retrieved during source verification — treat the + confirming its parameters was not retrieved during source verification – treat the principle as established curriculum practice rather than a citable primary finding. - title: Conoscopic Procedure @@ -63,7 +63,7 @@ sections: 1. Select a clean, well-polished large flat facet (ideally the table or a large pavilion main facet). 2. Orient the stone so the suspected optic axis is approximately perpendicular to the - facet being examined — this usually means examining the table facet of a well-cut + facet being examined – this usually means examining the table facet of a well-cut stone. 3. For round brilliants: the table facet is a good starting orientation; for elongated stones (marquise, oval), try both the table and a large pavilion facet. @@ -81,7 +81,7 @@ sections: - title: Uniaxial Interference Figure content: | - Crystals of the trigonal, tetragonal, and hexagonal systems are uniaxial — they have one + Crystals of the trigonal, tetragonal, and hexagonal systems are uniaxial – they have one optic axis (the c-axis). subsections: - title: Appearance of the Centred Uniaxial Figure @@ -89,11 +89,11 @@ sections: When the optic axis is perpendicular to the polished face, the centred uniaxial figure shows: - - A stationary dark **isogyre cross** (Maltese cross) — the cross arms run north-south + - A stationary dark **isogyre cross** (Maltese cross) – the cross arms run north-south and east-west and remain fixed as the stage rotates. - Concentric **isochromatic rings** surrounding the cross, corresponding to regions of equal retardation. Higher birefringence means more rings. - - The centre of the cross (where the arms intersect) is the **melatope** — the point + - The centre of the cross (where the arms intersect) is the **melatope** – the point where the optic axis emerges. - title: Off-Centre Figure @@ -121,7 +121,7 @@ sections: - title: Biaxial Interference Figure content: | - Crystals of the orthorhombic, monoclinic, and triclinic systems are biaxial — they have + Crystals of the orthorhombic, monoclinic, and triclinic systems are biaxial – they have two optic axes. subsections: - title: Acute Bisectrix (Bxa) Figure @@ -171,7 +171,7 @@ sections: - ["Topaz", "Orthorhombic", "Biaxial; two melatopes clearly separated", "Positive", "2V ~65°; good teaching example of biaxial figure"] - ["Sphene (titanite)", "Monoclinic", "Biaxial; complex figure", "Positive", "Very high birefringence; many rings; 2V ~17–40°"] - ["Tourmaline", "Trigonal", "Uniaxial; strong birefringence; many rings", "Negative", "Rings numerous; may be hard to count"] - - ["Peridot", "Orthorhombic", "Biaxial; nearly optic normal", "Positive", "2V ~82–90°; melatopes far apart — may need optic axis figure"] + - ["Peridot", "Orthorhombic", "Biaxial; nearly optic normal", "Positive", "2V ~82–90°; melatopes far apart – may need optic axis figure"] - title: Limitations callout: @@ -179,7 +179,7 @@ sections: title: Practical Constraints on Conoscopic Observation in Cut Gems text: | - **Optic axis orientation:** A usable figure requires the optic axis to be approximately - perpendicular to the table facet — this is not always achievable in a standard cut. + perpendicular to the table facet – this is not always achievable in a standard cut. - **Small stones:** Very small stones produce inadequate light convergence; minimum useful size is approximately 3 mm diameter. - **Included or turbid stones:** Reduce light transmission and obscure the figure. @@ -207,5 +207,5 @@ sections: determinations of the optic sign or optic character of a gemstone." *The Journal of Gemmology* 32(1–4), 90–100. DOI: 10.15506/jog.2010.32.1-4.90 [VERIFIED] - Hofmeister, A. M. & Mao, H.-K. (2002). American Mineralogist. - DOI: 10.2138/am-2002-0414 [APPROXIMATELY — paper is on IR polarised spectra; polariscope + DOI: 10.2138/am-2002-0414 [APPROXIMATELY – paper is on IR polarised spectra; polariscope operational description is curriculum-level] diff --git a/docs/learn/equipment/diamond-screening.yaml b/docs/learn/equipment/diamond-screening.yaml index c7bc2e7..18ba209 100644 --- a/docs/learn/equipment/diamond-screening.yaml +++ b/docs/learn/equipment/diamond-screening.yaml @@ -1,5 +1,5 @@ title: Diamond Screening Instruments -description: Thermal conductivity probes, electrical conductivity testers, DiamondView, DiamondSure, and reflectance meters — the tools used to screen loose diamonds and detect synthetic and simulant materials. +description: Thermal conductivity probes, electrical conductivity testers, DiamondView, DiamondSure, and reflectance meters – the tools used to screen loose diamonds and detect synthetic and simulant materials. order: 13 category: equipment difficulty: intermediate @@ -23,12 +23,12 @@ sections: Diamonds require dedicated screening instruments because their refractive index (2.417) and specific gravity (3.52) exceed the range of the standard gemmological refractometer and are therefore not directly confirmable by the standard tool set. The instruments on this page - address that gap — from rapid in-trade thermal probes through to laboratory-grade UV imaging + address that gap – from rapid in-trade thermal probes through to laboratory-grade UV imaging systems used to detect synthetic growth patterns. - title: Thermal Conductivity Probe content: | - **Principle:** Diamond has the highest thermal conductivity of any natural substance — + **Principle:** Diamond has the highest thermal conductivity of any natural substance – approximately 2000–2200 W·m⁻¹·K⁻¹, compared with ~100 W·m⁻¹·K⁻¹ for most gem minerals. A diamond tester consists of a heated tip; when pressed against the stone surface, the rate of heat dissipation is measured electronically. Diamond dissipates heat so rapidly that the meter @@ -37,7 +37,7 @@ sections: subsections: - title: Procedure content: | - 1. Allow the probe tip to warm to operating temperature — the LED ready indicator on + 1. Allow the probe tip to warm to operating temperature – the LED ready indicator on the unit confirms when the tip is at calibrated temperature. 2. Hold the stone firmly on a clean, flat surface. 3. Touch the probe tip perpendicularly to a polished facet with gentle, consistent @@ -50,7 +50,7 @@ sections: - title: Thermal Test Fails for Moissanite content: | **Moissanite (synthetic silicon carbide, SiC)** has a thermal conductivity of - approximately 490 W·m⁻¹·K⁻¹ — lower than diamond but high enough to trigger the + approximately 490 W·m⁻¹·K⁻¹ – lower than diamond but high enough to trigger the "diamond" reading on most standard single-probe thermal testers. Henn (2021) reported that synthetic moissanite testing as "diamond" using standard @@ -65,7 +65,7 @@ sections: content: | **Why electrical testing is needed:** Type IIb natural diamond (containing boron impurities) is a p-type semiconductor with measurable electrical conductivity. Most natural diamonds - (Type Ia, Ib, IIa) are electrical insulators. Moissanite is a semiconductor — it conducts + (Type Ia, Ib, IIa) are electrical insulators. Moissanite is a semiconductor – it conducts electricity at gem-testing voltages. **Dedicated moissanite testers** (combining thermal and electrical measurement) exploit this @@ -74,13 +74,13 @@ sections: | Result | Thermal | Electrical | Conclusion | |--------|---------|------------|------------| | Diamond (Type Ia/Ib/IIa) | High (diamond zone) | Insulator | Diamond | - | Diamond (Type IIb — blue/grey) | High | Conductor | Natural Type IIb diamond — do not reject as moissanite | + | Diamond (Type IIb – blue/grey) | High | Conductor | Natural Type IIb diamond – do not reject as moissanite | | Moissanite | High (passes thermal) | Conductor | Moissanite | | CZ and most simulants | Low (fails thermal) | Insulator | Non-diamond simulant | The combined thermal + electrical test discriminates all three major categories. When testing a blue or grey diamond suspected of being Type IIb: test thermally first, then - electrically — Type IIb will pass thermal and pass electrical, while moissanite also passes + electrically – Type IIb will pass thermal and pass electrical, while moissanite also passes both. Further confirmation (spectroscope: moissanite shows strong birefringence; diamond does not) is required for blue/grey stones. callout: @@ -88,7 +88,7 @@ sections: title: HPHT and CVD Synthetic Diamonds Cannot Be Detected by Probe Testers text: | HPHT and CVD synthetic diamonds (both colourless and coloured) test positive on both - thermal and combined electrical probes — they are genuine diamond (carbon) and have the + thermal and combined electrical probes – they are genuine diamond (carbon) and have the same thermal and electrical properties as natural diamond. Probe testers cannot distinguish synthetic diamond from natural diamond. For this, DiamondView, photoluminescence spectroscopy (77 K), or FTIR diamond type classification is required. @@ -96,7 +96,7 @@ sections: - title: DiamondView (Deep-UV Fluorescence Imaging) content: | **Principle:** DiamondView (a De Beers/Element Six instrument) irradiates the diamond surface - with very short-wavelength UV light below 230 nm — beyond the range of standard SW-UV lamps + with very short-wavelength UV light below 230 nm – beyond the range of standard SW-UV lamps (~254 nm). This deep UV excites strong surface fluorescence in diamond, revealing growth sector patterns. subsections: @@ -108,7 +108,7 @@ sections: - **Natural diamond:** typically blue or blue-green fluorescence; irregular, non-geometric patterns without sharp sector boundaries. - - **HPHT synthetic diamond:** characteristic cuboctahedral growth sector pattern — + - **HPHT synthetic diamond:** characteristic cuboctahedral growth sector pattern – distinct coloured sectors (blue, yellow-green, orange) in a geometrically regular arrangement corresponding to the growth faces ({111}, {100}, {110}). - **CVD synthetic diamond:** often orange-red or green striped fluorescence layers @@ -125,14 +125,14 @@ sections: Note: detailed DiamondView instrument specifications are proprietary and not available in open peer-reviewed literature. The descriptions above are synthesised from the peer-reviewed papers cited (Willems 2011, Wang 2007) and Gem-A Diploma teaching - materials. Willems et al. and Wang et al. are inferred use references — their papers + materials. Willems et al. and Wang et al. are inferred use references – their papers describe CVD diamond fluorescence as observed under DiamondView-like conditions. - title: DiamondView Limitations content: | - Does not work reliably on very small melee diamonds (below ~0.05 ct) where growth pattern detail is unresolvable. - - Cannot be used on stones set in jewellery — requires all-round UV illumination of the + - Cannot be used on stones set in jewellery – requires all-round UV illumination of the bare stone. - Training is required to interpret fluorescence patterns reliably. - Some natural Type IIa diamonds show unusual fluorescence that can be ambiguous. @@ -144,15 +144,15 @@ sections: N3 absorption line** (the Cape series diamond marker). Most natural diamonds are Type Ia and show the N3 line at 415.5 nm. Stones that lack this - line — Type IIa diamonds, CVD synthetic diamonds — are referred by DiamondSure for further + line – Type IIa diamonds, CVD synthetic diamonds – are referred by DiamondSure for further testing. The instrument issues a binary result: - - **"Pass"** — stone shows the N3 line, consistent with natural Type Ia diamond. - - **"Refer"** — stone lacks the N3 line; further laboratory testing is required. + - **"Pass"** – stone shows the N3 line, consistent with natural Type Ia diamond. + - **"Refer"** – stone lacks the N3 line; further laboratory testing is required. A "refer" result means the stone is unusual, **not** necessarily synthetic. Natural Type IIa diamonds (including some of the finest D-colour colourless stones) will always give a "refer" - result. DiamondSure only screens — it does not confirm synthetic origin. + result. DiamondSure only screens – it does not confirm synthetic origin. Note: the DiamondSure screening principle and its use of the 415 nm line are documented in Gem-A Diploma materials and in peer-reviewed papers (Breeding & Shigley 2009, DOI: @@ -169,7 +169,7 @@ sections: higher reflectance. This allows **approximate RI estimation** for stones whose RI exceeds the refractometer's - upper limit (~1.81) — making it useful for screening diamonds, moissanite, and high-RI + upper limit (~1.81) – making it useful for screening diamonds, moissanite, and high-RI simulants at the trade counter. subsections: - title: Reflectance Reference Values @@ -183,7 +183,7 @@ sections: - Notes rows: - ["Diamond (RI 2.417)", "~17", "Highest R of any natural gem; typical thermal probe positive"] - - ["Moissanite (SiC)", "~17", "Near-identical to diamond — cannot be separated by reflectance alone"] + - ["Moissanite (SiC)", "~17", "Near-identical to diamond – cannot be separated by reflectance alone"] - ["CZ (RI ~2.15)", "~13–14", "Clearly below diamond; fails thermal probe"] - ["Zircon (high, RI ~1.93)", "~10–11", "Well below diamond; useful for stones above refractometer range"] - ["Demantoid (RI ~1.89)", "~10", "Similar to zircon in R"] @@ -191,16 +191,16 @@ sections: - title: Important Limitations content: | - - **Moissanite cannot be separated from diamond by reflectance alone** — both give ~17% R. + - **Moissanite cannot be separated from diamond by reflectance alone** – both give ~17% R. The electrical conductivity test (see above) must be used first. - - Polished surface quality critically affects the reading — a scratched, frosted, or dirty + - Polished surface quality critically affects the reading – a scratched, frosted, or dirty facet gives erroneously low R. - Some instruments display an RI estimate computed from measured R using the Fresnel equation. The accuracy of such an estimate is limited and was not confirmed in - retrieved primary literature during source verification — treat as approximate guidance + retrieved primary literature during source verification – treat as approximate guidance only; do not rely on it for definitive RI determination. - Hodgkinson (2016) reported anomalous reflectance meter behaviour on a Sumitomo - synthetic diamond — illustrating that synthetic diamonds can produce unexpected readings: + synthetic diamond – illustrating that synthetic diamonds can produce unexpected readings: Journal of Gemmology 35(4), 274–275 (DOI: 10.15506/jog.2016.35.4.274) [VERIFIED]. - title: When to Refer to a Laboratory diff --git a/docs/learn/equipment/dichroscope.yaml b/docs/learn/equipment/dichroscope.yaml index 023cef0..5642a15 100644 --- a/docs/learn/equipment/dichroscope.yaml +++ b/docs/learn/equipment/dichroscope.yaml @@ -21,8 +21,8 @@ sections: It's essential for identifying coloured anisotropic gems and can help distinguish natural from synthetic materials. - Pleochroism—the property of showing different colours in different crystallographic - directions—is diagnostic for many coloured gemstones. + Pleochroism – the property of showing different colours in different crystallographic + directions – is diagnostic for many coloured gemstones. - title: Types of Dichroscope content: | @@ -110,10 +110,10 @@ sections: - ["Ruby", "Trigonal", "Strong", "O-ray: purplish red / E-ray: orange-red", "Best seen in thick stones"] - ["Blue sapphire", "Trigonal", "Strong", "O-ray: deep blue / E-ray: greenish-blue", "Varies with saturation"] - ["Emerald", "Hexagonal", "Distinct", "O-ray: blue-green / E-ray: yellow-green", "More visible in darker stones"] - - ["Tanzanite", "Orthorhombic", "Very strong", "α: blue / β: violet / γ: purple-red", "Trichroic — heat treated shows 2 colours"] + - ["Tanzanite", "Orthorhombic", "Very strong", "α: blue / β: violet / γ: purple-red", "Trichroic – heat treated shows 2 colours"] - ["Alexandrite", "Orthorhombic", "Very strong", "α: green / β: orange / γ: red-purple", "Colour change + strong pleochroism"] - ["Andalusite", "Orthorhombic", "Very strong", "α: yellow-green / β: brown-green / γ: red-brown", "Distinctive multicolour effect"] - - ["Iolite", "Orthorhombic", "Very strong", "α: violet-blue / β: blue / γ: pale yellow", "Water sapphire — dramatic colours"] + - ["Iolite", "Orthorhombic", "Very strong", "α: violet-blue / β: blue / γ: pale yellow", "Water sapphire – dramatic colours"] - ["Kunzite", "Monoclinic", "Distinct", "α: colourless / β: pink / γ: violet", "Fades in light over time"] - ["Tourmaline (green)", "Trigonal", "Strong", "O-ray: dark green / E-ray: light green", "Best viewed down c-axis"] - ["Tourmaline (pink)", "Trigonal", "Strong", "O-ray: dark pink / E-ray: light pink", "Orientation important for cutting"] diff --git a/docs/learn/equipment/other-tools.yaml b/docs/learn/equipment/other-tools.yaml index c7a4029..a87571d 100644 --- a/docs/learn/equipment/other-tools.yaml +++ b/docs/learn/equipment/other-tools.yaml @@ -58,7 +58,7 @@ sections: - ["Zambian emerald", "Weak/greenish", "—", "Higher Fe, lower Cr"] - ["Synthetic emerald", "—", "Very strong red", "Often higher Cr than natural"] - ["Ruby", "Strong red (brighter)", "Very strong red", "Cr fluorescence"] - - ["Blue sapphire", "Remains blue", "Remains blue", "No Cr — no reaction"] + - ["Blue sapphire", "Remains blue", "Remains blue", "No Cr – no reaction"] - ["Alexandrite", "Red (enhanced)", "Very strong red", "Strong Cr content"] - ["Demantoid garnet", "Greenish", "—", "Cr present but weak reaction"] - ["Green tourmaline", "Remains green", "—", "No Cr content"] @@ -201,10 +201,10 @@ sections: - Safety rows: - ["Water (baseline)", "1.00", "None (all gems sink)", "All gemstones", "Safe"] - - ["Toluene", "0.87", "Amber (SG 0.96–1.10)", "All other gems", "Toxic fumes — use fume hood"] - - ["Bromoform", "2.89", "Quartz, feldspar, beryl, opal", "Tourmaline, diamond, corundum", "Toxic — use gloves"] - - ["Methylene iodide (pure)", "3.32", "Quartz, beryl, tourmaline", "Diamond, corundum, spinel, topaz", "Very toxic — gloves + fume hood"] - - ["MI + toluene (diluted)", "3.06", "Quartz, beryl, tourmaline hovers", "Diamond, corundum, topaz", "Toxic — gloves + fume hood"] + - ["Toluene", "0.87", "Amber (SG 0.96–1.10)", "All other gems", "Toxic fumes – use fume hood"] + - ["Bromoform", "2.89", "Quartz, feldspar, beryl, opal", "Tourmaline, diamond, corundum", "Toxic – use gloves"] + - ["Methylene iodide (pure)", "3.32", "Quartz, beryl, tourmaline", "Diamond, corundum, spinel, topaz", "Very toxic – gloves + fume hood"] + - ["MI + toluene (diluted)", "3.06", "Quartz, beryl, tourmaline hovers", "Diamond, corundum, topaz", "Toxic – gloves + fume hood"] - ["Clerici solution", "4.25", "Diamond, corundum, topaz, spinel", "Zircon, cassiterite", "Toxic and corrosive"] - title: Float/Sink Reference by Gem @@ -239,9 +239,9 @@ sections: - Use only in well-ventilated areas or fume hoods - Wear appropriate gloves and safety glasses - - Never mouth-pipette — use bulb pipettes + - Never mouth-pipette – use bulb pipettes - Store in sealed containers away from light (prevents decomposition) - - Never use with porous or fractured stones — liquid can be absorbed + - Never use with porous or fractured stones – liquid can be absorbed - Dispose according to hazardous waste regulations Many modern laboratories prefer hydrostatic weighing due to safety concerns. diff --git a/docs/learn/equipment/overview.yaml b/docs/learn/equipment/overview.yaml index b62d685..4b4f77d 100644 --- a/docs/learn/equipment/overview.yaml +++ b/docs/learn/equipment/overview.yaml @@ -25,7 +25,7 @@ sections: forms the core practical skills tested in the FGA Foundation examination. A systematic approach using multiple instruments provides the most reliable identification. - No single test is definitive—results should be correlated across several methods. + No single test is definitive – results should be correlated across several methods. - title: The Gemmological Toolkit content: | diff --git a/docs/learn/equipment/polariscope.yaml b/docs/learn/equipment/polariscope.yaml index 40025ca..4ceb5cd 100644 --- a/docs/learn/equipment/polariscope.yaml +++ b/docs/learn/equipment/polariscope.yaml @@ -38,7 +38,7 @@ sections: - title: Crossed Polars Position content: | When the polariser and analyser are at 90° to each other, light cannot - pass through—the field appears dark. This is the "crossed polars" position + pass through – the field appears dark. This is the "crossed polars" position used for most tests. When aligned parallel, maximum light passes through (bright field). diff --git a/docs/learn/equipment/refractometer.yaml b/docs/learn/equipment/refractometer.yaml index 58d7447..cfd00d6 100644 --- a/docs/learn/equipment/refractometer.yaml +++ b/docs/learn/equipment/refractometer.yaml @@ -125,15 +125,15 @@ sections: subsections: - title: "Patterns I-III: Isotropic and Uniaxial" content: | - **Pattern I** — A single constant shadow edge confirms the material is isotropic. + **Pattern I** – A single constant shadow edge confirms the material is isotropic. Ensure the reading stays truly constant during a full rotation. - **Pattern II** — Two constant, parallel shadow edges that never move. This occurs when + **Pattern II** – Two constant, parallel shadow edges that never move. This occurs when the c-axis is perpendicular to the table facet. The minimum and maximum RI and birefringence can be determined, but the optic sign cannot without testing on an alternative facet. - **Pattern III** — One constant and one variable edge that join together at one point + **Pattern III** – One constant and one variable edge that join together at one point during rotation. This confirms uniaxial character with the c-axis parallel to the table. The optic sign is determinable: @@ -142,16 +142,16 @@ sections: - title: "Patterns IV-VII: Biaxial Determination" content: | - **Pattern IV** — One constant edge, one variable edge, not touching. This ambiguous + **Pattern IV** – One constant edge, one variable edge, not touching. This ambiguous pattern can occur in both uniaxial (oblique c-axis) and biaxial stones. - **Pattern V** — Shadow edges intersect (cross each other). This confirms biaxial + **Pattern V** – Shadow edges intersect (cross each other). This confirms biaxial character. The edges may both converge towards beta. - **Pattern VI** — Both edges move but do not touch. Confirms biaxial, but the optic + **Pattern VI** – Both edges move but do not touch. Confirms biaxial, but the optic sign cannot be determined without additional information. - **Pattern VII** — Both edges move and touch at one point. Confirms biaxial with + **Pattern VII** – Both edges move and touch at one point. Confirms biaxial with determinable optic sign. - title: Optic Sign Determination @@ -164,7 +164,7 @@ sections: **Biaxial optic sign** (when both edges move): - Observe which shadow edge crosses the point halfway between the maximum - (gamma) and minimum (alpha) values — this edge gives beta + (gamma) and minimum (alpha) values – this edge gives beta - Beta closer to alpha → **biaxial positive** - Beta closer to gamma → **biaxial negative** diff --git a/docs/learn/equipment/sg-measurement.yaml b/docs/learn/equipment/sg-measurement.yaml index 83086d8..880557a 100644 --- a/docs/learn/equipment/sg-measurement.yaml +++ b/docs/learn/equipment/sg-measurement.yaml @@ -1,5 +1,5 @@ title: Specific Gravity Measurement -description: Hydrostatic weighing and heavy-liquid methods for measuring specific gravity — the density-based property used to identify and confirm gem species. +description: Hydrostatic weighing and heavy-liquid methods for measuring specific gravity – the density-based property used to identify and confirm gem species. order: 10 category: equipment difficulty: beginner @@ -18,7 +18,7 @@ tags: sections: - title: Introduction content: | - Specific gravity (SG) — also called relative density — is the ratio of a substance's weight + Specific gravity (SG) – also called relative density – is the ratio of a substance's weight to the weight of an equal volume of water. It is a fundamental physical property that helps identify gem species, particularly when refractive index and optical tests are inconclusive. @@ -52,24 +52,24 @@ sections: subsections: - title: Required Components content: | - - **Analytical balance** — single-pan electronic or two-pan beam balance; ±0.01 g + - **Analytical balance** – single-pan electronic or two-pan beam balance; ±0.01 g resolution minimum (±0.001 g preferred for stones below 0.5 g) - - **Bridge or cradle frame** — mounted over or beside the balance pan; holds the beaker + - **Bridge or cradle frame** – mounted over or beside the balance pan; holds the beaker of water while the stone hangs suspended below on a wire - - **Fine wire sling or fibre-basket** — suspends the stone fully immersed without + - **Fine wire sling or fibre-basket** – suspends the stone fully immersed without touching the beaker walls or base - **Beaker of distilled water** with one drop of wetting agent (household detergent) to reduce surface tension and prevent air bubbles - - **Thermometer** — for temperature corrections if precision is required - - **Tweezers** — for stone handling; avoid fingers which add grease + - **Thermometer** – for temperature corrections if precision is required + - **Tweezers** – for stone handling; avoid fingers which add grease - title: Procedure content: | 1. Tare the balance with the wire sling hanging freely in air above the beaker. 2. Place the stone in the sling, lower it so it hangs freely in air. Record **W_air**. - 3. Raise the beaker of distilled water so the stone is fully immersed — check no + 3. Raise the beaker of distilled water so the stone is fully immersed – check no air bubbles are visible on the stone surface; gently agitate if needed. - 4. Record **W_water** (the apparent weight under water — numerically less than W_air). + 4. Record **W_water** (the apparent weight under water – numerically less than W_air). 5. Calculate: **SG = W_air / (W_air − W_water)**. 6. Repeat at least twice; take the mean. @@ -94,7 +94,7 @@ sections: This gives a rapid qualitative SG bracket in seconds. Liquids may be diluted (with acetone for organic liquids, or water for sodium polytungstate) to adjust density to intermediate values. Shannon (1985) described the gemmological use of heavy liquids in Gems & Gemology - (DOI: 10.1080/00357529.1985.11764366) [PARTIALLY_SUPPORTED — title and DOI confirmed; + (DOI: 10.1080/00357529.1985.11764366) [PARTIALLY_SUPPORTED – title and DOI confirmed; abstract not retrieved]. table: caption: Heavy Liquids Used in Gemmological Laboratories @@ -105,15 +105,15 @@ sections: - Hazard Class - Status rows: - - ["Di-iodomethane (CH₂I₂)", "Methylene iodide", "~3.32 at 20 °C", "Toxic vapour; photodegrades; stains skin", "Still in common use — handle in fume cupboard"] + - ["Di-iodomethane (CH₂I₂)", "Methylene iodide", "~3.32 at 20 °C", "Toxic vapour; photodegrades; stains skin", "Still in common use – handle in fume cupboard"] - ["Bromoform (CHBr₃)", "Bromoform", "~2.89 at 20 °C", "Toxic; suspected carcinogen; volatile", "Being phased out in many laboratories"] - - ["Clerici solution (thallium formate–malonate)", "Clerici", "Up to ~4.2 (adjustable)", "Acutely toxic — thallium absorbed through skin", "Banned or restricted in many jurisdictions; avoid"] + - ["Clerici solution (thallium formate–malonate)", "Clerici", "Up to ~4.2 (adjustable)", "Acutely toxic – thallium absorbed through skin", "Banned or restricted in many jurisdictions; avoid"] - ["Sodium polytungstate (Na₆[H₂W₁₂O₄₀])", "SPT", "~2.7–3.1 (adjustable with water)", "Non-toxic; water-soluble", "Modern alternative; does not reach 3.32+ SG range"] - title: Safety callout: type: warning - title: Heavy Liquid Hazards — Read Before Use + title: Heavy Liquid Hazards – Read Before Use text: | **Clerici solution** is the most dangerous heavy liquid used in gemmological laboratories. It contains thallium salts; thallium is absorbed through intact skin and mucous membranes, @@ -121,9 +121,9 @@ sections: use under COSHH regulations. Where Clerici is still used: full PPE (nitrile gloves, fume cupboard, closed containers) is mandatory. **Never use Clerici without training.** - **Di-iodomethane:** toxic vapour — use in ventilated area or fume cupboard. + **Di-iodomethane:** toxic vapour – use in ventilated area or fume cupboard. Photodegrades on exposure to light/air (turns brown/orange; store in amber bottles). - Can irreversibly stain organic gems (pearls, amber, coral) — not suitable for these. + Can irreversibly stain organic gems (pearls, amber, coral) – not suitable for these. **Bromoform:** volatile, toxic, possible carcinogen; not to be used without fume cupboard. @@ -151,10 +151,10 @@ sections: - ["Corundum (ruby/sapphire)", "3.80–4.05", "Sinks", "Sinks", "Wide range due to Fe/Ti content"] - ["Spinel (natural)", "3.58–3.61", "Sinks", "Sinks", "Isotropic"] - ["Spinel (Verneuil synthetic)", "3.61–3.67", "Sinks", "Sinks", "Slightly higher than natural"] - - ["Topaz", "3.50–3.60", "Sinks", "Sinks", "Perfect basal cleavage — handle carefully"] + - ["Topaz", "3.50–3.60", "Sinks", "Sinks", "Perfect basal cleavage – handle carefully"] - ["Peridot", "3.32–3.37", "Floats / suspends", "Sinks", "SG overlaps di-iodomethane closely"] - ["Jadeite", "3.30–3.36", "Floats / suspends", "Sinks", "Aggregate material"] - - ["Nephrite", "2.80–3.10", "Floats", "Floats / suspends", "Lower than jadeite — useful diagnostic"] + - ["Nephrite", "2.80–3.10", "Floats", "Floats / suspends", "Lower than jadeite – useful diagnostic"] - ["Beryl (all varieties)", "2.65–2.80", "Floats", "Floats", "Includes emerald, aquamarine, morganite"] - ["Quartz (crystalline)", "2.65", "Floats", "Floats", "Very consistent; useful balance calibration standard"] - ["Amber", "1.05–1.10", "Floats", "Floats", "Floats in saturated salt water (SG ~1.13)"] @@ -166,16 +166,16 @@ sections: subsections: - title: Measurement Errors content: | - - **Air bubbles on the stone surface** — reduce the apparent weight of displaced water, + - **Air bubbles on the stone surface** – reduce the apparent weight of displaced water, giving a falsely high SG reading. Remove by gently agitating or by using a wetting agent in the water. - - **Mounted stones** — metal settings introduce unknown mass; the method is unreliable + - **Mounted stones** – metal settings introduce unknown mass; the method is unreliable for set stones without dismounting. - - **Porous or treated stones** — water absorption (opal, turquoise, some coral) alters + - **Porous or treated stones** – water absorption (opal, turquoise, some coral) alters the reading over time as the stone absorbs liquid. - - **Very small stones** — weighing error becomes proportionally large; minimum useful + - **Very small stones** – weighing error becomes proportionally large; minimum useful stone weight is approximately 0.15–0.20 g for ±0.01 g balance resolution. - - **Fracture-filled stones** — filler material (glass, resin) changes the apparent SG + - **Fracture-filled stones** – filler material (glass, resin) changes the apparent SG from the host mineral. - title: Balance Calibration @@ -196,7 +196,7 @@ sections: - Mitchell (1980). "Anderson on Heavy Liquids." *The Journal of Gemmology* 17(4), 230. DOI: 10.15506/jog.1980.17.4.230 [VERIFIED] - Shannon (1985). "Determining Specific Gravity Using Heavy Liquids." *Gems & Gemology*. - DOI: 10.1080/00357529.1985.11764366 [PARTIALLY_SUPPORTED — title and DOI confirmed; + DOI: 10.1080/00357529.1985.11764366 [PARTIALLY_SUPPORTED – title and DOI confirmed; abstract not retrieved] - Munsterman, D. & Kerstholt, S. (1996). "Sodium polytungstate, a new non-toxic alternative to bromoform in heavy liquid separation." *Review of Palaeobotany and Palynology* 91, diff --git a/docs/learn/equipment/spectroscope.yaml b/docs/learn/equipment/spectroscope.yaml index f069d64..088dc11 100644 --- a/docs/learn/equipment/spectroscope.yaml +++ b/docs/learn/equipment/spectroscope.yaml @@ -180,14 +180,14 @@ sections: - Some gem species show no diagnostic spectrum - Laboratory spectrometers provide more detailed analysis - - title: Named Absorption Spectra — Foundation Tier + - title: Named Absorption Spectra – Foundation Tier content: | The twelve species below form the core absorption-spectrum vocabulary for the FGA Foundation examination. Each spectrum must be recognisable by principal line(s) and overall pattern. **Note on wavelength values:** Several nm values in this table are sourced from Read, P. G. (ed.), *Gemmology* (commonly referenced as "Read 7th ed.", Butterworth-Heinemann), which - is the standard Gem-A teaching textbook. These values are [PARTIALLY_SUPPORTED] — the + is the standard Gem-A teaching textbook. These values are [PARTIALLY_SUPPORTED]; the chromophore assignments and general spectral patterns are confirmed by peer-reviewed DOI-verified sources (Fritsch & Rossman 1987, DOI: 10.5741/gems.23.3.126; Dubinsky et al. 2020, DOI: 10.5741/gems.56.1.2; Breeding & Shigley 2009, DOI: 10.5741/gems.45.2.96; @@ -196,55 +196,55 @@ sections: but the precise nm values for some secondary lines derive from the textbook and are not independently verifiable via abstract APIs. table: - caption: Foundation Tier — 12 Core Absorption Spectra + caption: Foundation Tier – 12 Core Absorption Spectra headers: - Species - Principal Lines (nm) - Chromophore - Diagnostic Strength rows: - - ["Ruby (natural + Verneuil)", "692.8 + 694.2 doublet; 668, 659; broad ~550 absorption; 468; UV cutoff ~400", "Cr³⁺", "Highest — doublet + luminescent glow in red light"] - - ["Emerald (natural)", "683 + 680 doublet; 662, 646; broad ~580–630; blue-violet absorption; 477 (some stones)", "Cr³⁺ (± Fe³⁺ in Fe-rich stones)", "High — doublet diagnostic; Fe bands vary by origin"] - - ["Blue sapphire", "450 strong narrow; 460, 470 weaker; broad Fe²⁺–Ti⁴⁺ CT absorption", "Fe³⁺ + Fe²⁺–Ti⁴⁺ charge transfer", "High — 450 nm line in virtually all blue sapphire"] - - ["Almandine garnet", "504, 520, 573 broad bands; weaker 423, 461, 610, 680, 690", "Fe²⁺", "Highest — three-band pattern virtually diagnostic"] - - ["Pyrope garnet", "504, 520, 573 (Fe²⁺); chromiferous: broad ~575 + 685–687 (Cr³⁺)", "Fe²⁺ ± Cr³⁺", "Moderate — Fe bands shared with almandine"] - - ["Spessartine garnet", "410, 421, 432 strong (Mn²⁺); violet edge cutoff", "Mn²⁺", "Highest — Mn triplet unique to spessartine"] - - ["Demantoid garnet", "~440 nm cutoff (Fe³⁺); Russian type: 618, 634, 685, 701 (Cr³⁺)", "Fe³⁺ ± Cr³⁺", "High — 440 cutoff separates from green idocrase"] - - ["Peridot", "493, 473, 453 three evenly spaced bands (Fe²⁺)", "Fe²⁺", "Highest — three-iron-band pattern essentially diagnostic"] - - ["Zircon (high / Sri Lanka type)", "653.5 principal; 691, 662, 660, 621, 615, 589, 562, 537, 516, 484, 460 fine lines", "U⁴⁺", "Highest — picket-fence multi-line pattern unmistakeable"] - - ["Diamond (Cape series / Type Ia)", "415.5 (N3 centre); 478 (N2); 465, 451, 435, 423, 401 weaker vibronic series", "Nitrogen aggregate (N3, N2 defect centres)", "High — 415.5 nm canonical Cape yellow marker"] - - ["Red spinel (natural)", "656, 665, 685 narrow Cr³⁺ lines; broad ~540 absorption", "Cr³⁺", "High — organ pipe triplet separates from ruby (694 nm doublet)"] - - ["Zircon (low / metamict)", "653.5 diffuse or absent; featureless or very broad", "U⁴⁺ (amorphised lattice)", "Low — contrast with high zircon confirms metamict character"] + - ["Ruby (natural + Verneuil)", "692.8 + 694.2 doublet; 668, 659; broad ~550 absorption; 468; UV cutoff ~400", "Cr³⁺", "Highest – doublet + luminescent glow in red light"] + - ["Emerald (natural)", "683 + 680 doublet; 662, 646; broad ~580–630; blue-violet absorption; 477 (some stones)", "Cr³⁺ (± Fe³⁺ in Fe-rich stones)", "High – doublet diagnostic; Fe bands vary by origin"] + - ["Blue sapphire", "450 strong narrow; 460, 470 weaker; broad Fe²⁺–Ti⁴⁺ CT absorption", "Fe³⁺ + Fe²⁺–Ti⁴⁺ charge transfer", "High – 450 nm line in virtually all blue sapphire"] + - ["Almandine garnet", "504, 520, 573 broad bands; weaker 423, 461, 610, 680, 690", "Fe²⁺", "Highest – three-band pattern virtually diagnostic"] + - ["Pyrope garnet", "504, 520, 573 (Fe²⁺); chromiferous: broad ~575 + 685–687 (Cr³⁺)", "Fe²⁺ ± Cr³⁺", "Moderate – Fe bands shared with almandine"] + - ["Spessartine garnet", "410, 421, 432 strong (Mn²⁺); violet edge cutoff", "Mn²⁺", "Highest – Mn triplet unique to spessartine"] + - ["Demantoid garnet", "~440 nm cutoff (Fe³⁺); Russian type: 618, 634, 685, 701 (Cr³⁺)", "Fe³⁺ ± Cr³⁺", "High – 440 cutoff separates from green idocrase"] + - ["Peridot", "493, 473, 453 three evenly spaced bands (Fe²⁺)", "Fe²⁺", "Highest – three-iron-band pattern essentially diagnostic"] + - ["Zircon (high / Sri Lanka type)", "653.5 principal; 691, 662, 660, 621, 615, 589, 562, 537, 516, 484, 460 fine lines", "U⁴⁺", "Highest – picket-fence multi-line pattern unmistakeable"] + - ["Diamond (Cape series / Type Ia)", "415.5 (N3 centre); 478 (N2); 465, 451, 435, 423, 401 weaker vibronic series", "Nitrogen aggregate (N3, N2 defect centres)", "High – 415.5 nm canonical Cape yellow marker"] + - ["Red spinel (natural)", "656, 665, 685 narrow Cr³⁺ lines; broad ~540 absorption", "Cr³⁺", "High – organ pipe triplet separates from ruby (694 nm doublet)"] + - ["Zircon (low / metamict)", "653.5 diffuse or absent; featureless or very broad", "U⁴⁺ (amorphised lattice)", "Low – contrast with high zircon confirms metamict character"] - - title: Named Absorption Spectra — Diploma Extension Tier + - title: Named Absorption Spectra – Diploma Extension Tier content: | The sixteen species below extend the Foundation spectra list to Diploma level, covering additional corundum varieties, tourmalines, secondary garnets, and selected rare species. The same note on textbook-sourced nm values applies (see Foundation tier heading above). table: - caption: Diploma Tier — 16 Extended Absorption Spectra + caption: Diploma Tier – 16 Extended Absorption Spectra headers: - Species - Principal Lines (nm) - Chromophore - Diagnostic Strength rows: - - ["Alexandrite (chrysoberyl)", "680.5 + 678.5 doublet; 655, 645; broad ~580 (colour-change band); broad ~420–450", "Cr³⁺", "High — doublet shifted from ruby (694 nm) and emerald (683 nm)"] - - ["Yellow sapphire", "450 (Fe³⁺, if present); broad tailing into violet; often absent in pale stones", "Fe³⁺ ± colour centre", "Low–moderate — spectrum often very weak; RI/SG primary"] - - ["Green sapphire", "471, 460, 450 (Fe²⁺/Fe³⁺)", "Fe²⁺ + Fe³⁺", "Moderate — modified blue sapphire pattern"] - - ["Padparadscha sapphire", "450 (Fe³⁺); broad violet colour-centre absorption", "Fe³⁺ + colour centre", "Low — combination not uniquely diagnostic; colour description primary"] - - ["Colombian vs Zambian emerald", "Colombia: Cr doublet 683/680, Fe bands weak/absent; Zambia: same doublet + stronger Fe absorption + possible 477 nm line", "Cr³⁺ ± Fe³⁺", "Moderate — Fe-band presence/absence aids origin discrimination; not conclusive alone"] - - ["Tsavorite garnet (chrome grossular)", "Broad ~630 (V³⁺/Cr³⁺); broad ~450; weak 433 (Mn²⁺ if present)", "V³⁺ ± Cr³⁺ ± Mn²⁺", "Moderate — no single sharp diagnostic line; RI/SG more reliable"] - - ["Rhodolite garnet (pyrope-almandine)", "504, 520, 573 (Fe²⁺); Cr³⁺ shoulder ~680–687 if chromiferous", "Fe²⁺ ± Cr³⁺", "Moderate — identical to almandine/pyrope; SG/RI differentiate"] - - ["Indicolite tourmaline", "Broad ~720 (Fe²⁺ d-d); broad UV cutoff 300–400 (O²⁻–Fe³⁺ CT)", "Fe²⁺ + Fe²⁺–Fe³⁺ IVCT", "Moderate — gradual cutoff, no sharp lines; contrast with blue sapphire 450 nm line"] - - ["Rubellite tourmaline", "Broad ~520 (Mn³⁺); no sharp lines", "Mn³⁺", "Moderate — broad green absorption; no lines (contrast with red spinel organ pipe)"] - - ["Chrome tourmaline", "~680 (Cr³⁺); broad green/blue absorption", "Cr³⁺", "Moderate–high — Cr line position less sharp than ruby or emerald"] - - ["Aquamarine (blue beryl)", "537, 456, 427 (Fe²⁺ + Fe³⁺); often weak", "Fe²⁺ + Fe³⁺", "Low–moderate — spectrum frequently faint in pale stones"] - - ["Tanzanite (heat-treated blue zoisite)", "Broad ~450–460 (V³⁺ along α-axis); broad ~520 (V³⁺)", "V³⁺ ± Ti³⁺/⁴⁺", "Moderate — broad V band; trichroism is stronger diagnostic indicator"] - - ["Jadeite", "437 narrow (Fe³⁺, most jadeite); imperial green: broad ~630–650 + ~690 (Cr³⁺)", "Fe³⁺ ± Cr³⁺", "Moderate — 437 nm separates from nephrite (which lacks this line)"] - - ["Chrome diopside", "Broad ~670 (Cr³⁺); ~690 narrow-moderate Cr R-lines", "Cr³⁺", "Moderate — broad 670 band similar to but distinguishable from ruby and demantoid"] - - ["Sphene (titanite)", "~580–585 doublet (Nd³⁺ + Pr³⁺ REE); additional sharp REE lines", "Nd³⁺, Pr³⁺ (rare earth)", "Moderate — didymium REE pattern + extraordinary dispersion makes misidentification unlikely"] - - ["Synthetic emerald (flux, e.g. Chatham) vs natural", "Cr doublet 683/680 present; Fe-related bands (477 nm, blue-violet) absent or very weak", "Cr³⁺ (Fe absent)", "Moderate — Fe-band absence supports synthetic; also consistent with Fe-poor Colombian natural; microscopy required for confirmation"] + - ["Alexandrite (chrysoberyl)", "680.5 + 678.5 doublet; 655, 645; broad ~580 (colour-change band); broad ~420–450", "Cr³⁺", "High – doublet shifted from ruby (694 nm) and emerald (683 nm)"] + - ["Yellow sapphire", "450 (Fe³⁺, if present); broad tailing into violet; often absent in pale stones", "Fe³⁺ ± colour centre", "Low–moderate – spectrum often very weak; RI/SG primary"] + - ["Green sapphire", "471, 460, 450 (Fe²⁺/Fe³⁺)", "Fe²⁺ + Fe³⁺", "Moderate – modified blue sapphire pattern"] + - ["Padparadscha sapphire", "450 (Fe³⁺); broad violet colour-centre absorption", "Fe³⁺ + colour centre", "Low – combination not uniquely diagnostic; colour description primary"] + - ["Colombian vs Zambian emerald", "Colombia: Cr doublet 683/680, Fe bands weak/absent; Zambia: same doublet + stronger Fe absorption + possible 477 nm line", "Cr³⁺ ± Fe³⁺", "Moderate – Fe-band presence/absence aids origin discrimination; not conclusive alone"] + - ["Tsavorite garnet (chrome grossular)", "Broad ~630 (V³⁺/Cr³⁺); broad ~450; weak 433 (Mn²⁺ if present)", "V³⁺ ± Cr³⁺ ± Mn²⁺", "Moderate – no single sharp diagnostic line; RI/SG more reliable"] + - ["Rhodolite garnet (pyrope-almandine)", "504, 520, 573 (Fe²⁺); Cr³⁺ shoulder ~680–687 if chromiferous", "Fe²⁺ ± Cr³⁺", "Moderate – identical to almandine/pyrope; SG/RI differentiate"] + - ["Indicolite tourmaline", "Broad ~720 (Fe²⁺ d-d); broad UV cutoff 300–400 (O²⁻–Fe³⁺ CT)", "Fe²⁺ + Fe²⁺–Fe³⁺ IVCT", "Moderate – gradual cutoff, no sharp lines; contrast with blue sapphire 450 nm line"] + - ["Rubellite tourmaline", "Broad ~520 (Mn³⁺); no sharp lines", "Mn³⁺", "Moderate – broad green absorption; no lines (contrast with red spinel organ pipe)"] + - ["Chrome tourmaline", "~680 (Cr³⁺); broad green/blue absorption", "Cr³⁺", "Moderate–high – Cr line position less sharp than ruby or emerald"] + - ["Aquamarine (blue beryl)", "537, 456, 427 (Fe²⁺ + Fe³⁺); often weak", "Fe²⁺ + Fe³⁺", "Low–moderate – spectrum frequently faint in pale stones"] + - ["Tanzanite (heat-treated blue zoisite)", "Broad ~450–460 (V³⁺ along α-axis); broad ~520 (V³⁺)", "V³⁺ ± Ti³⁺/⁴⁺", "Moderate – broad V band; trichroism is stronger diagnostic indicator"] + - ["Jadeite", "437 narrow (Fe³⁺, most jadeite); imperial green: broad ~630–650 + ~690 (Cr³⁺)", "Fe³⁺ ± Cr³⁺", "Moderate – 437 nm separates from nephrite (which lacks this line)"] + - ["Chrome diopside", "Broad ~670 (Cr³⁺); ~690 narrow-moderate Cr R-lines", "Cr³⁺", "Moderate – broad 670 band similar to but distinguishable from ruby and demantoid"] + - ["Sphene (titanite)", "~580–585 doublet (Nd³⁺ + Pr³⁺ REE); additional sharp REE lines", "Nd³⁺, Pr³⁺ (rare earth)", "Moderate – didymium REE pattern + extraordinary dispersion makes misidentification unlikely"] + - ["Synthetic emerald (flux, e.g. Chatham) vs natural", "Cr doublet 683/680 present; Fe-related bands (477 nm, blue-violet) absent or very weak", "Cr³⁺ (Fe absent)", "Moderate – Fe-band absence supports synthetic; also consistent with Fe-poor Colombian natural; microscopy required for confirmation"] - title: Try the Interactive Tool callout: diff --git a/docs/learn/equipment/uv-lamp.yaml b/docs/learn/equipment/uv-lamp.yaml index 3f9268f..d171d7c 100644 --- a/docs/learn/equipment/uv-lamp.yaml +++ b/docs/learn/equipment/uv-lamp.yaml @@ -123,7 +123,7 @@ sections: subsections: - title: What Is Phosphorescence? content: | - Phosphorescence is delayed fluorescence—the gem continues to emit light + Phosphorescence is delayed fluorescence – the gem continues to emit light for seconds to minutes after the UV source is removed. This "afterglow" can be diagnostic for certain materials. diff --git a/docs/learn/fundamentals/chemical-properties.yaml b/docs/learn/fundamentals/chemical-properties.yaml index ef70b97..35fac4e 100644 --- a/docs/learn/fundamentals/chemical-properties.yaml +++ b/docs/learn/fundamentals/chemical-properties.yaml @@ -217,7 +217,7 @@ sections: - Diagnostic Notes rows: - ["Chrysoberyl", "Fe", "Band centred at 444 nm", "Distinguishes yellow/greenish/brown chrysoberyl from sapphire; useful for cat's eyes in settings"] - - ["Alexandrite", "Cr", "Lines in red; broad band in yellow-green", "Pleochroic variation visible — spectrum shifts between daylight and tungsten light"] + - ["Alexandrite", "Cr", "Lines in red; broad band in yellow-green", "Pleochroic variation visible – spectrum shifts between daylight and tungsten light"] - ["Synthetic colour-change sapphire", "V + Cr", "Sharp fine line at 475 nm", "Diagnostic for vanadium in corundum; line may be faint"] - ["Jadeite (pale specimens)", "Fe", "Fine line at 437 nm", "Seen in pale specimens of various colours; green stones may also show Cr lines in red"] - ["Dyed jadeite", "Fe + Cr-dye", "Weak band(s) in red + 437 nm line", "Chromium-green dye gives additional band(s) in red; diagnostic for dye detection"] @@ -280,7 +280,7 @@ sections: electrons can move throughout the crystal structure at a higher energy level than those bound within atomic orbitals. The gap between the atom-bound "valence band" electrons and the wandering "conduction band" electrons is the electron energy band - gap — a "forbidden" zone whose width greatly influences optical properties. + gap – a "forbidden" zone whose width greatly influences optical properties. subsections: - title: Three Material Types content: | @@ -289,7 +289,7 @@ sections: 1. **Large band gap** (wider than visible light range): Even violet light cannot excite electrons across the gap. No visible light is absorbed, so the material appears transparent and colourless when pure. Most gemstones fall into this - category — pure diamond, corundum, quartz, and topaz. + category – pure diamond, corundum, quartz, and topaz. 2. **Small band gap** (narrower than red light energy): All visible light interacts with electrons and is absorbed, making the material opaque. @@ -312,7 +312,7 @@ sections: extending into lower-energy visible light. Higher-energy blue and violet light is transmitted, producing blue colour. Because the boron level is close to the valence band, electrons can be thermally excited at room temperature, leaving "holes" that - allow electrical current — boron-containing diamonds conduct electricity. + allow electrical current – boron-containing diamonds conduct electricity. - title: Physical Optics Colour content: | @@ -344,14 +344,14 @@ sections: thin films, layers of differing composition, or thin-film cavities such as cracks. When two reflected rays travel in the same direction and their wave peaks coincide ("in phase"), they reinforce each other. When peak meets trough ("out of phase"), - they cancel — this is interference. + they cancel – this is interference. Examples in gemmology: - **Labradorite**: iridescent colours from interference at thin compositional layers - **Pearl nacre**: lustre from diffraction at overlapping platy aragonite crystals combined with interference from thin nacre layers - **Crack iridescence**: colours from thin films of air in cracks (as in topaz, - glass, or quartz) — similar to oil films on water + glass, or quartz) – similar to oil films on water - title: Scattering content: | @@ -363,7 +363,7 @@ sections: where scattering is caused by submicroscopic particles of albite feldspar. As particles get larger, other colours such as red and green may be seen at certain - angles. Larger particles still produce a whitish effect called opalescence — seen in + angles. Larger particles still produce a whitish effect called opalescence – seen in materials such as common opal and milky quartz. This should not be confused with the play-of-colour effect in precious opal. diff --git a/docs/learn/fundamentals/colour-theory.yaml b/docs/learn/fundamentals/colour-theory.yaml index 41b0b1a..4bfe76e 100644 --- a/docs/learn/fundamentals/colour-theory.yaml +++ b/docs/learn/fundamentals/colour-theory.yaml @@ -1,5 +1,5 @@ title: Colour Theory in Gemmology -description: The physics and chemistry of gem colour — crystal field theory, charge transfer, colour centres, allochromatic and idiochromatic minerals, and band-gap colouration. +description: "The physics and chemistry of gem colour: crystal field theory, charge transfer, colour centres, allochromatic and idiochromatic minerals, and band-gap colouration." order: 3.2 category: fundamentals difficulty: advanced @@ -18,18 +18,18 @@ tags: - allochromatic sections: - - title: Overview — The Four Main Causes of Colour + - title: Overview – The Four Main Causes of Colour content: | Kurt Nassau's classification (Nassau, *The Physics and Chemistry of Color*, 2nd ed., 2001) identifies fifteen mechanisms of colour in minerals, of which four are central to gemmology: - 1. **Crystal field theory (d–d transitions)** — the dominant mechanism for chromophore transition + 1. **Crystal field theory (d–d transitions)** – the dominant mechanism for chromophore transition metals in most coloured gem species (Cr³⁺ in ruby and emerald, Fe²⁺ in peridot). - 2. **Charge transfer** — electron transfer between adjacent ions; responsible for blue sapphire + 2. **Charge transfer** – electron transfer between adjacent ions; responsible for blue sapphire and aquamarine colour. - 3. **Colour centres** — defects in the crystal lattice that trap electrons or holes and absorb + 3. **Colour centres** – defects in the crystal lattice that trap electrons or holes and absorb visible light; responsible for smoky quartz, amethyst, blue topaz, and coloured diamond. - 4. **Band-gap (semiconductor) absorption** — the entire conduction band absorbs photons above + 4. **Band-gap (semiconductor) absorption** – the entire conduction band absorbs photons above the gap energy; explains the pure colourlessness of type IIa diamond and the vivid red of cinnabar. @@ -46,7 +46,7 @@ sections: **Mechanism:** - In an octahedral coordination site (6 O²⁻ ligands), the d-orbitals split into a lower set (t₂g) and a higher set (eɡ), separated by the crystal field splitting energy Δ_oct. - - In a tetrahedral site (4 ligands), the splitting Δ_tet ≈ 4/9 Δ_oct — smaller, producing + - In a tetrahedral site (4 ligands), the splitting Δ_tet ≈ 4/9 Δ_oct – smaller, producing weaker colour. - The energy Δ determines the absorbed wavelength (E = hc/λ); a larger Δ absorbs shorter, higher-energy wavelengths. @@ -61,7 +61,7 @@ sections: *Source: Nassau, pp. 101–153 [VERIFIED]; Read 3rd ed., DOI: 10.4324/9780080507224 [VERIFIED]* subsections: - - title: Ruby — Cr³⁺ in corundum (Al₂O₃) + - title: Ruby – Cr³⁺ in corundum (Al₂O₃) content: | Al³⁺ octahedral sites are comparatively small; the strong field around Cr³⁺ gives Δ_oct large enough to produce broad absorption at ~410 nm (violet–blue) and ~560 nm (yellow–green), @@ -73,7 +73,7 @@ sections: **Chelsea Colour Filter reaction:** strongly red (Cr³⁺ transmits deep red and absorbs green). - - title: Emerald — Cr³⁺ in beryl (Be₃Al₂Si₆O₁₈) + - title: Emerald – Cr³⁺ in beryl (Be₃Al₂Si₆O₁₈) content: | The same Cr³⁺ ion sits in a slightly larger Al³⁺ octahedral site in beryl compared with corundum, shifting Δ to smaller values. The absorption bands move to slightly longer @@ -84,10 +84,10 @@ sections: identical d–d mechanism. Chrome emeralds appear red through the Chelsea Colour Filter; vanadium emeralds may appear red–orange or inert depending on V concentration. - - title: Alexandrite — dual transmission window + - title: Alexandrite – dual transmission window content: | Alexandrite (Cr³⁺ in chrysoberyl, BeAl₂O₄) is the classic example of the alexandrite - effect. The Cr³⁺ crystal field in chrysoberyl produces two transmission windows — + effect. The Cr³⁺ crystal field in chrysoberyl produces two transmission windows: one in the red (~680 nm) and a narrower one in the blue–green (~580 nm region excluded and ~470–490 nm transmitted). @@ -98,25 +98,25 @@ sections: *Source: Nassau 2001, pp. 112–115 [PARTIALLY_SUPPORTED]; F-009 confirmed in principle* - - title: Peridot — Fe²⁺ in olivine + - title: Peridot – Fe²⁺ in olivine content: | Fe²⁺ in the M1 and M2 octahedral sites of olivine (Mg₂SiO₄) produces three distinct - absorption bands at approximately 493 nm, 473 nm, and 453 nm — the classic three-banded + absorption bands at approximately 493 nm, 473 nm, and 453 nm – the classic three-banded iron spectrum visible in the spectroscope. The yellow-green colour results from this triplet absorbing blue and leaving yellow-green transmitted. The relatively weak crystal field around Fe²⁺ in olivine results in smaller Δ values compared with Cr³⁺ in corundum, which is why the colour is yellow-green rather than red. - **Peridot is idiochromatic** — Fe²⁺ is an essential constituent of gem-quality olivine. + **Peridot is idiochromatic**: Fe²⁺ is an essential constituent of gem-quality olivine. *Source: Nassau, pp. 108–112 [VERIFIED]* - title: Charge-Transfer Colouration content: | - Charge transfer (CT) colour arises when an electron is transferred between two adjacent ions - — either between two metal ions (intervalence charge transfer, IVCT) or from oxygen to a - metal (ligand-to-metal charge transfer, LMCT) — rather than remaining on a single ion as + Charge transfer (CT) colour arises when an electron is transferred between two adjacent ions, + either between two metal ions (intervalence charge transfer, IVCT) or from oxygen to a + metal (ligand-to-metal charge transfer, LMCT), rather than remaining on a single ion as in d–d transitions. **Mechanism:** @@ -134,19 +134,19 @@ sections: *Source: Nassau, pp. 184–210 [VERIFIED]; Dubinsky 2020, DOI: 10.5741/gems.56.1.2 [VERIFIED]* subsections: - - title: Blue sapphire — Fe²⁺–Ti⁴⁺ IVCT in corundum + - title: Blue sapphire – Fe²⁺–Ti⁴⁺ IVCT in corundum content: | Nassau's canonical IVCT example. The Fe–Ti pair on alternating face-sharing octahedral sites absorbs strongly in the yellow–red (peaking ~550–700 nm), leaving blue–violet transmitted. Spectroscope shows three broad, unresolved bands at approximately 450 nm, - 460 nm, and 470 nm — the diagnostic blue sapphire triplet. + 460 nm, and 470 nm – the diagnostic blue sapphire triplet. No sharp Cr fluorescence lines; no red CCF reaction (no Cr³⁺ unless the sapphire is deliberately Cr-bearing, as in some Sri Lanka padparadscha). *Source: Dubinsky et al. 2020, DOI: 10.5741/gems.56.1.2 [VERIFIED]* - - title: Aquamarine — Fe²⁺–Fe³⁺ IVCT in beryl + - title: Aquamarine – Fe²⁺–Fe³⁺ IVCT in beryl content: | Fe²⁺ and Fe³⁺ on adjacent sites in the beryl channel structure produce a broad absorption band in the yellow–red, leaving blue transmitted. The spectroscope shows @@ -155,13 +155,13 @@ sections: Indicolite tourmaline (blue) carries a similar Fe²⁺–Fe³⁺ IVCT colour. Kyanite blue is also attributed to this IVCT mechanism. - - title: Yellow sapphire — Fe³⁺ LMCT + - title: Yellow sapphire – Fe³⁺ LMCT content: | Fe³⁺ alone (without Ti⁴⁺ to form IVCT pairs) absorbs in the UV, with the absorption tail cutting into the blue end of the visible, leaving yellow–orange transmitted. Some orange sapphires combine Fe³⁺ LMCT with Cr³⁺ d–d bands. - - title: Diagnostic contrast — CT vs d–d + - title: Diagnostic contrast – CT vs d–d content: | A gemmologist can distinguish CT-coloured stones from d–d-coloured stones by: @@ -173,9 +173,9 @@ sections: - title: Colour Centres content: | - A colour centre is a localised lattice defect — typically an electron (F-centre) or a hole - (h-centre) trapped at a structural imperfection such as an anion vacancy or adjacent to a - substitutional impurity — that absorbs visible light and creates colour in an otherwise + A colour centre is a localised lattice defect (typically an electron F-centre or a hole + h-centre) trapped at a structural imperfection such as an anion vacancy or adjacent to a + substitutional impurity, that absorbs visible light and creates colour in an otherwise colourless material. **Mechanism:** @@ -183,7 +183,7 @@ sections: trapped electron absorbs photons to move between energy levels of the defect potential. - **Hole centre:** an unpaired electron hole trapped adjacent to a substitutional cation. In quartz, Al³⁺ substituting for Si⁴⁺ creates a charge imbalance; irradiation leaves an - AlO₄ unit with a trapped hole — the [AlO₄]⁰ centre. + AlO₄ unit with a trapped hole: the [AlO₄]⁰ centre. - **Irradiation** (natural γ/α/β or artificial neutron/electron beam) creates centres by displacing atoms and generating vacancies. The stability of the centre determines whether colour is permanent or fades. @@ -194,7 +194,7 @@ sections: *Source: Nassau, pp. 211–250 [VERIFIED]; Nassau & Prescott 1977, DOI: 10.1180/minmag.1977.041.319.01 [VERIFIED]* subsections: - - title: Smoky quartz — Al–O hole centre + - title: Smoky quartz – Al–O hole centre content: | Al³⁺ substituting for Si⁴⁺ in quartz, combined with natural or artificial irradiation, produces a hole trapped at the AlO₄ unit (the [AlO₄]⁰ centre). Nassau & Prescott (1977) @@ -204,16 +204,16 @@ sections: *Source: Nassau & Prescott 1977, DOI: 10.1180/minmag.1977.041.319.01 [VERIFIED]* - - title: Amethyst — Fe⁴⁺ hole centre + - title: Amethyst – Fe⁴⁺ hole centre content: | Fe³⁺ substituting for Si⁴⁺ in quartz, under irradiation, produces an [FeO₄]⁰ centre - (Fe⁴⁺ — a hole localised on iron). This centre absorbs at ~520 nm (green), transmitting + (Fe⁴⁺, a hole localised on iron). This centre absorbs at ~520 nm (green), transmitting purple-violet. Heating above ~450 °C converts Fe⁴⁺ back to Fe³⁺, producing yellow citrine. This transformation is exploited commercially to produce heat-treated citrine from amethyst. - - title: Blue topaz — irradiation-induced colour centres + - title: Blue topaz – irradiation-induced colour centres content: | Natural blue topaz is rare. Commercial blue topaz is produced by neutron or electron irradiation of colourless topaz, creating colour centres that absorb in the yellow–red @@ -222,13 +222,13 @@ sections: The irradiated origin must be disclosed in trade (treated material). The colour mechanism distinguishes blue topaz (colour centre, heat-sensitive) from aquamarine (Fe IVCT, stable). - - title: Diamond colour centres — N3, NV, H3 + - title: Diamond colour centres – N3, NV, H3 content: | Nitrogen defects in diamond create several named optical centres: - **N3 centre** (three N atoms + vacancy): responsible for Cape blue-white fluorescence under LWUV and the 415 nm absorption line (Cape series). Characteristic of type Ia - diamond — the most common natural diamond type. Spectroscopic literature gives 415.5 nm + diamond – the most common natural diamond type. Spectroscopic literature gives 415.5 nm for the zero-phonon line. - **NV⁻ centre** (nitrogen–vacancy pair, negative charge): zero-phonon line at 637 nm; produces pink to red photoluminescence. Found in pink diamonds and exploited in @@ -239,19 +239,19 @@ sections: diamonds. Detected by photoluminescence at 77 K. HPHT treatment of brown type IIa diamond anneals out vacancy-related brown centres, - destroying N3 characteristic fluorescence — detectable by FTIR and DiamondView. + destroying N3 characteristic fluorescence, detectable by FTIR and DiamondView. *Source: Hainschwang 2012, DOI: 10.5741/gems.48.4.252 [VERIFIED]; Nassau 2001, pp. 227–235 [VERIFIED]* - - title: Maxixe beryl — unstable colour centre + - title: Maxixe beryl – unstable colour centre content: | Deep blue beryl from the Maxixe mine, Minas Gerais, Brazil, owes its colour to an irradiation-induced colour centre (involving NO₃⁻ or CO₃²⁻ radical anions substituting - in the beryl channel — the precise identity remains under study). + in the beryl channel; the precise identity remains under study). The centre is unstable in ambient light and fades to pale pink or colourless over months - of daylight exposure — the gemmological standard case of light-bleachable colour. + of daylight exposure, making it the standard gemmological example of light-bleachable colour. This distinguishes maxixe beryl from aquamarine (Fe IVCT, stable) and irradiated blue topaz (different centre, stable at room temperature). @@ -279,7 +279,7 @@ sections: - **Idiochromatic:** the colouring element is a required component of the mineral formula. Even an ideal, pure crystal will be coloured. The colour range is narrow. - **Pseudochromatic:** colour-like effects produced by light interference, diffraction, or - scattering — not electronic absorption. No chromophore is involved; the apparent colour + scattering, not electronic absorption. No chromophore is involved; the apparent colour changes with viewing angle or disappears when the specimen is oriented edge-on. *Source: Nassau, pp. 100–104 [VERIFIED]* @@ -319,7 +319,7 @@ sections: - title: Band-Gap Colouration content: | - In crystalline solids with a band structure, colour arises when the band gap (Eg — the energy + In crystalline solids with a band structure, colour arises when the band gap (Eg, the energy difference between the valence band and the conduction band) falls within or near the visible range. Photons with energy > Eg are absorbed; those with energy < Eg are transmitted. diff --git a/docs/learn/fundamentals/crystal-systems.yaml b/docs/learn/fundamentals/crystal-systems.yaml index f0ac9da..44c5876 100644 --- a/docs/learn/fundamentals/crystal-systems.yaml +++ b/docs/learn/fundamentals/crystal-systems.yaml @@ -278,7 +278,7 @@ sections: - ["Orthorhombic", "mmm", "Holohedral", "Topaz; peridot/olivine; tanzanite/zoisite; andalusite; danburite"] - ["Trigonal", "3", "Polar, enantiomorphic", "—"] - ["Trigonal", "3̄", "Centrosymmetric", "—"] - - ["Trigonal", "32", "Enantiomorphic", "Quartz (explains optical activity — left/right handed)"] + - ["Trigonal", "32", "Enantiomorphic", "Quartz (explains optical activity – left/right handed)"] - ["Trigonal", "3m", "Polar", "Tourmaline (piezoelectric/pyroelectric); calcite group"] - ["Trigonal", "3̄m", "Holohedral", "Corundum (ruby, sapphire); hematite"] - ["Hexagonal", "6", "Polar, enantiomorphic", "—"] @@ -303,7 +303,7 @@ sections: and shows the Brazil and Dauphiné twin laws. No centre of inversion → piezoelectric. - **Tourmaline (point group 3m):** polar axis along c responsible for piezoelectricity and pyroelectricity. The polar nature also produces pyroelectric discharge when temperature - changes — tourmaline crystals attract dust. + changes – tourmaline crystals attract dust. - **Corundum (point group 3̄m):** has a centre of inversion (the 3̄ inversion axis); therefore neither piezoelectric nor optically active. Uniaxial negative with pleochroism oriented along the c-axis. @@ -316,30 +316,30 @@ sections: type: info title: Point Group vs Crystal System text: | - Each crystal system contains multiple point groups — not a single one. A crystal system + Each crystal system contains multiple point groups – not a single one. A crystal system defines the axial geometry; the point group specifies the exact symmetry elements present. - For example, the trigonal system contains point groups 3, 3̄, 32, 3m, and 3̄m — each + For example, the trigonal system contains point groups 3, 3̄, 32, 3m, and 3̄m – each giving different physical properties (optical activity, piezoelectricity, centrosymmetry). - - title: Miller Indices — 3-Index and 4-Index Notation + - title: Miller Indices – 3-Index and 4-Index Notation content: | Miller indices {hkl} describe the orientation of a crystal face or plane by the reciprocals of its fractional intercepts on the crystallographic axes. - **Three-index notation {hkl}** — used for cubic, tetragonal, orthorhombic, monoclinic, and + **Three-index notation {hkl}** – used for cubic, tetragonal, orthorhombic, monoclinic, and triclinic systems (three axes: a, b, c): - {100}: intercepts a at 1, parallel to b and c. - - {111}: intercepts all three axes equally — the octahedral face in cubic. - - {110}: intercepts a and b at 1, parallel to c — the dodecahedral face in cubic. + - {111}: intercepts all three axes equally – the octahedral face in cubic. + - {110}: intercepts a and b at 1, parallel to c – the dodecahedral face in cubic. - **Four-index (Bravais–Miller) notation {hkil}** — required for trigonal and hexagonal + **Four-index (Bravais–Miller) notation {hkil}** – required for trigonal and hexagonal systems, which have three equivalent horizontal axes (a₁, a₂, a₃) at 120° and one vertical c-axis: - The **closure relation** i = −(h+k) always holds; i is not an independent variable but makes the symmetry equivalence of faces explicit in the notation. - {10-10}: the hexagonal prism face. i = -(1+0) = -1, confirming h + k + i = 0. - - {0001}: the basal pinacoid — perpendicular to the c-axis; the "table" of a hexagonal crystal. - - {10-11}: the rhombohedral face in trigonal — the twin and parting plane of corundum. + - {0001}: the basal pinacoid – perpendicular to the c-axis; the "table" of a hexagonal crystal. + - {10-11}: the rhombohedral face in trigonal – the twin and parting plane of corundum. **Why the redundant index?** In a 6-fold-symmetric hexagonal crystal there are six equivalent prism faces. The 4-index notation makes this equivalence explicit: {10-10}, @@ -369,7 +369,7 @@ sections: Diploma level. The only formula to remember is: **i = −(h+k)**. Understanding this relation explains why trigonal/hexagonal crystals have 6-fold or - 3-fold equivalence of side faces — each set of equivalent faces has the same set of + 3-fold equivalence of side faces – each set of equivalent faces has the same set of |h|, |k|, |i| values in different permutations. - title: Parting (False Cleavage) @@ -379,9 +379,9 @@ sections: repeated twinning lamellae or by exsolution of a second phase along a crystallographic plane. **Distinction from cleavage:** - - **Cleavage** is universal — every crystal of the species will cleave along the same planes, + - **Cleavage** is universal – every crystal of the species will cleave along the same planes, because the planes reflect inherently weak bonds in the crystal structure. - - **Parting** is contingent — only crystals that happen to be twinned or to have undergone + - **Parting** is contingent – only crystals that happen to be twinned or to have undergone exsolution show parting. It may be restricted to parts of the crystal and is not universal across all specimens of the species. @@ -393,10 +393,10 @@ sections: Corundum (ruby and sapphire) has no true cleavage. It shows two parting directions from polysynthetic twinning: - - **{10-11} rhombohedral parting** — the most prominent; arises from repeated polysynthetic + - **{10-11} rhombohedral parting** – the most prominent; arises from repeated polysynthetic twinning on the rhombohedral plane. Visible as parallel flat steps on broken corundum rough, and as iridescent flat internal planes in faceted stones. - - **{0001} basal parting** — from twinning on the basal pinacoid; less consistent. + - **{0001} basal parting** – from twinning on the basal pinacoid; less consistent. A common Diploma examination error is stating "corundum has perfect basal cleavage." The correct answer is: corundum has **no cleavage**; the flat surfaces observed are diff --git a/docs/learn/fundamentals/crystallography-advanced.yaml b/docs/learn/fundamentals/crystallography-advanced.yaml index ed56def..75f9d76 100644 --- a/docs/learn/fundamentals/crystallography-advanced.yaml +++ b/docs/learn/fundamentals/crystallography-advanced.yaml @@ -24,7 +24,7 @@ sections: and crystal morphology. The FGA Diploma requires ability to draw common crystal habits and understand - twinning patterns—these visual skills are tested in examinations. + twinning patterns – these visual skills are tested in examinations. - title: Miller Indices content: | diff --git a/docs/learn/fundamentals/optic-sign-determination.yaml b/docs/learn/fundamentals/optic-sign-determination.yaml index ed658ed..49b706e 100644 --- a/docs/learn/fundamentals/optic-sign-determination.yaml +++ b/docs/learn/fundamentals/optic-sign-determination.yaml @@ -31,10 +31,10 @@ sections: - **Biaxial negative (B−):** β is closer to γ: γ − β < β − α. The optic sign can be determined by two methods: - 1. **Refractometer rotation** (uniaxial stones only) — observing which shadow edge moves as + 1. **Refractometer rotation** (uniaxial stones only) – observing which shadow edge moves as the stone is rotated. - 2. **Conoscopic interference figure** with an accessory plate (lambda plate or quartz wedge) - — reading the colour change in the isochromatic rings. + 2. **Conoscopic interference figure** with an accessory plate (lambda plate or quartz wedge), + reading the colour change in the isochromatic rings. The interference-figure method uses **Newton's colour series** (the interference colour sequence seen between crossed polars as retardation increases): yellow → orange → red → @@ -46,12 +46,12 @@ sections: *Source: Sturman, B.D., J. Gemmology, 2007. DOI: 10.15506/jog.2007.30.7.443. [VERIFIED]; Read, P., Gemmology 3rd ed. DOI: 10.4324/9780080507224 [VERIFIED]* - - title: Uniaxial Procedure — Refractometer Method + - title: Uniaxial Procedure – Refractometer Method content: | For uniaxial stones with measurable birefringence, the refractometer can be used directly: 1. Place the stone table-down on the refractometer hemisphere with contact liquid. - 2. Observe the shadow edge (or edges). A uniaxial stone shows two shadow edges — + 2. Observe the shadow edge (or edges). A uniaxial stone shows two shadow edges – the fixed edge (ω, ordinary ray) and the moving edge (ε, extraordinary ray). 3. Rotate the stone slowly through 360°. The ε edge moves; the ω edge stays fixed. 4. If the moving edge (ε) is **above** the fixed edge (ω) at maximum separation: @@ -63,7 +63,7 @@ sections: (c-axis pointing up into the contact liquid), both readings coincide as a single shadow edge at the ω position. Rotate the stone off this orientation to see both edges. - - title: Uniaxial Procedure — Interference Figure (Lambda Plate) + - title: Uniaxial Procedure – Interference Figure (Lambda Plate) content: | The conoscope (convergent polarised light through the polariscope, using a high-powered condensing lens or the stone itself as a condenser) produces an interference figure for @@ -84,12 +84,12 @@ sections: retardations add → colours **rise** in Newton's series (toward blue, 2nd order). - In the other two quadrants: retardations subtract → colours **fall** (toward yellow). - **Reading the sign (principle — without committing to a specific diagram convention):** + **Reading the sign (principle – without committing to a specific diagram convention):** The orientation rule for the plate-in-figure is described in standard optical mineralogy texts (Read 3rd ed.; Sturman 2007). The key relationship is: in the quadrants where the crystal's slow ray aligns with the plate slow direction, rising colours indicate the slow - direction of the crystal in that quadrant — from which the sign follows. Consult your + direction of the crystal in that quadrant – from which the sign follows. Consult your course's specific diagram orientation, as the convention depends on the physical direction the plate is inserted relative to the polariser/analyser orientation. @@ -111,10 +111,10 @@ sections: with the plate oriented differently. Learn the principle (addition = rising colour in the slow-slow quadrant) and apply it consistently to your instrument setup. - - title: Biaxial Procedure — Acute Bisectrix Figure + - title: Biaxial Procedure – Acute Bisectrix Figure content: | For biaxial stones, the acute bisectrix (Bxa) interference figure is used. The stone must - be oriented with the acute bisectrix perpendicular to the polariscope stage — typically + be oriented with the acute bisectrix perpendicular to the polariscope stage – typically requiring the stone to be oriented by trial and error (or by knowledge of the optic orientation of the species). @@ -165,7 +165,7 @@ sections: the isochromatic rings to tiny concentric circles near the melatope; the lambda plate effect is harder to read. Thinner sections (or smaller stones) help. - **Low birefringence:** very low birefringence (e.g. apatite 0.002–0.006) produces very few - or no isochromatic rings — the figure shows only the isogyre cross against a near-uniform + or no isochromatic rings – the figure shows only the isogyre cross against a near-uniform background. The lambda plate still produces a colour shift in the quadrants; read the shift in the area immediately around the melatope. - **Dauphiné twinning in quartz:** sector-by-sector anomalous extinction can mimic biaxial diff --git a/docs/learn/fundamentals/optical-properties.yaml b/docs/learn/fundamentals/optical-properties.yaml index f119eda..8e17add 100644 --- a/docs/learn/fundamentals/optical-properties.yaml +++ b/docs/learn/fundamentals/optical-properties.yaml @@ -81,7 +81,7 @@ sections: content: | Birefringence is the difference between maximum and minimum RI values in anisotropic (non-cubic) crystals. Light entering the stone splits into two - rays traveling at different speeds. + rays travelling at different speeds. **Formula:** `Birefringence = RI(max) - RI(min)` @@ -179,7 +179,7 @@ sections: text: | Practise with our interactive optical property tools: - - [Refractometer simulator](/tools/optical) — practise reading shadow edges - - [Dichroscope lookup](/tools/optical) — identify gems by observed colours - - [Polariscope guide](/tools/optical) — interpret isotropic vs anisotropic reactions - - [RI calculator](/tools/calculator) — look up gems by refractive index + - [Refractometer simulator](/tools/optical) – practise reading shadow edges + - [Dichroscope lookup](/tools/optical) – identify gems by observed colours + - [Polariscope guide](/tools/optical) – interpret isotropic vs anisotropic reactions + - [RI calculator](/tools/calculator) – look up gems by refractive index diff --git a/docs/learn/fundamentals/physical-properties.yaml b/docs/learn/fundamentals/physical-properties.yaml index 45ba776..b2ff3b4 100644 --- a/docs/learn/fundamentals/physical-properties.yaml +++ b/docs/learn/fundamentals/physical-properties.yaml @@ -25,7 +25,7 @@ sections: - title: Hardness content: | Hardness measures a mineral's resistance to scratching. The **Mohs scale** - ranks minerals from 1 (talc) to 10 (diamond), but the scale is not linear—diamond + ranks minerals from 1 (talc) to 10 (diamond), but the scale is not linear – diamond is approximately 140 times harder than corundum. table: caption: Mohs Scale Reference @@ -185,7 +185,7 @@ sections: *Note*: Many heavy liquids are toxic and restricted. Di-iodomethane discolours during storage and should be stored in a dark bottle. Heavy liquid SG will vary - slightly with temperature and differential evaporation — values should be taken + slightly with temperature and differential evaporation – values should be taken as approximate. - title: SG Accuracy and Limitations @@ -220,7 +220,7 @@ sections: - title: Jadeite content: | Older pieces of jadeite polished with softer materials may exhibit an "orange peel" - surface — an irregular polish on a fine scale caused by the polycrystalline + surface – an irregular polish on a fine scale caused by the polycrystalline structure, in which randomly oriented grains each present different hardness directions to the polishing powder. Diamond powder gives an even polish in all directions regardless of this effect. A similar undercutting effect is also seen @@ -285,8 +285,8 @@ sections: similar to cleavage and is sometimes called "false cleavage". Unlike cleavage, which is an inherent property of the crystal structure found - throughout a material, parting occurs only along specific planes of weakness — - typically twin boundaries — and is not found in all specimens of a species. + throughout a material, parting occurs only along specific planes of weakness – + typically twin boundaries – and is not found in all specimens of a species. subsections: - title: Parting in Corundum content: | @@ -295,7 +295,7 @@ sections: the crystal and is not present in all corundum specimens. Parting can be mistaken for cleavage during examination, but true cleavage - in corundum does not exist — the rhombohedral "cleavage" observed is + in corundum does not exist – the rhombohedral "cleavage" observed is actually parting along twin planes. - title: Thermal Conductivity @@ -341,7 +341,7 @@ sections: Most synthetic moissanite (SiC) is an electrical semiconductor, while natural diamond (except rare Type IIb blue) is an insulator. - - title: Tenacity — Resistance to Mechanical Deformation + - title: Tenacity – Resistance to Mechanical Deformation content: | Tenacity describes how a mineral resists breaking, bending, or deformation. It is distinct from hardness (resistance to scratching) and from cleavage (the mode of fracture). The @@ -355,7 +355,7 @@ sections: gemmological standards. - **Sectile:** can be cut with a knife into shavings without crumbling; deforms plastically under a sharp edge. Not common in gem minerals; talc (H1) is sectile. - - **Malleable:** can be hammered into thin sheets without crumbling. Metals only — native + - **Malleable:** can be hammered into thin sheets without crumbling. Metals only – native gold inclusions in quartz are malleable. - **Ductile:** can be drawn into a wire. Native gold, platinum. Not a gemmological property of the gem minerals themselves. @@ -375,11 +375,11 @@ sections: - Diagnostic application rows: - ["Brittle", "Diamond, corundum, quartz, tourmaline, topaz, garnet, spinel", "Most faceted gems; conchoidal or uneven fracture surface"] - - ["Tough", "Nephrite (H 6–6.5), jadeite (H 6.5–7)", "Nephrite tougher than diamond despite lower hardness — fibrous interlocking structure"] + - ["Tough", "Nephrite (H 6–6.5), jadeite (H 6.5–7)", "Nephrite tougher than diamond despite lower hardness – fibrous interlocking structure"] - ["Sectile", "Amber (slightly under knife), talc", "Amber can be shaved; relevant in amber vs plastic vs copal testing"] - ["Malleable", "Native gold (inclusion in quartz)", "Gold leaf inclusions spread under pressure"] - ["Flexible (not elastic)", "Talc, chlorite, gypsum selenite", "Chlorite inclusions in gems flex under probe but do not spring back"] - - ["Elastic", "Muscovite, phlogopite mica", "Mica inclusions spring back when probe is removed — distinguishes from chlorite"] + - ["Elastic", "Muscovite, phlogopite mica", "Mica inclusions spring back when probe is removed – distinguishes from chlorite"] - title: Toughness vs hardness content: | @@ -390,7 +390,7 @@ sections: Nephrite jade (H 6–6.5) is tougher than diamond (H 10) because its densely interlocking fibrous tremolite–actinolite structure prevents crack propagation. Diamond, despite maximum - hardness, has perfect octahedral cleavage and brittle tenacity — a sharp blow in the {111} + hardness, has perfect octahedral cleavage and brittle tenacity – a sharp blow in the {111} direction will cleave it. - title: Magnetism in Gems @@ -457,10 +457,10 @@ sections: **Derivation:** At Brewster's angle, the reflected and refracted beams are at 90°. By Snell's law: n₁ sin(θ_B) = n₂ sin(90° − θ_B) = n₂ cos(θ_B), giving tan(θ_B) = n₂/n₁ = n. - **Worked example — diamond:** + **Worked example – diamond:** n(diamond) = 2.417; θ_B = arctan(2.417) = approximately 67.5°. At this angle, light reflected from the diamond surface vibrates only in the plane - perpendicular to the plane of incidence — fully polarised. + perpendicular to the plane of incidence – fully polarised. A polaroid filter held at the appropriate angle above a gem surface eliminates surface glare at Brewster's angle, improving transparency during examination. The immersion method @@ -473,7 +473,7 @@ sections: - title: Brewster angle reference values content: | The values below are calculated from the formula θ_B = arctan(n) using the known RI - of each gem material. Brewster's angle increases with RI — higher-RI stones require a + of each gem material. Brewster's angle increases with RI – higher-RI stones require a steeper angle of incidence to achieve full polarisation of the reflected beam. table: caption: Brewster angle calculated from RI (formula confirmed; individual RI values from Read 3rd ed.) @@ -497,7 +497,7 @@ sections: measurement of high-RI stones such as diamond (2.417), CZ (2.17), and high zircon (up to 1.99). - - title: Dispersion — Named Values (B–G Interval) + - title: Dispersion – Named Values (B–G Interval) content: | Dispersion in gemmology is measured as the difference in refractive index between the Fraunhofer B line (686.7 nm, red) and the G line (430.8 nm, violet): @@ -514,7 +514,7 @@ sections: *Source: Read, Gemmology 3rd ed. DOI: 10.4324/9780080507224 [VERIFIED]; Nassau, Physics and Chemistry of Color, 2001, pp. 52–56 [VERIFIED]* table: - caption: Dispersion (B–G interval) for gem materials — CZ value is 0.060 (Read 7th; VERIFIED; NOT 0.065) + caption: Dispersion (B–G interval) for gem materials – CZ value is 0.060 (Read 7th; VERIFIED; NOT 0.065) headers: - Material - Dispersion (B–G) @@ -523,7 +523,7 @@ sections: - ["Rutile (TiO₂ synthetic)", "0.280", "Extreme; rarely faceted due to very high birefringence"] - ["Strontium titanate (SrTiO₃)", "0.190", "Synthetic; formerly 'fabulite'; highest of gem simulants"] - ["Synthetic moissanite (SiC)", "0.104", "Higher than diamond; noticeable fire in faceted stones"] - - ["Cubic zirconia (ZrO₂)", "0.060", "Higher than diamond; conspicuous fire — diagnostic vs. diamond (Read 3rd ed. confirmed)"] + - ["Cubic zirconia (ZrO₂)", "0.060", "Higher than diamond; conspicuous fire – diagnostic vs. diamond (Read 3rd ed. confirmed)"] - ["Sphene / titanite", "0.051", "Very high; 'adamantine to sub-adamantine' fire; visible coloured flashes"] - ["Demantoid garnet", "0.057", "Highest of natural garnets; visible fire even through green bodycolour"] - ["GGG (gadolinium gallium garnet)", "0.045", "Synthetic diamond simulant"] @@ -539,7 +539,7 @@ sections: callout: type: warning - title: CZ Dispersion — Confirmed Value + title: CZ Dispersion – Confirmed Value text: | Cubic zirconia dispersion = **0.060** (Read, Gemmology 3rd ed.; DOI-verified source). A figure of 0.065 sometimes appears in trade literature but is unverified by a peer-reviewed @@ -552,7 +552,7 @@ sections: text: | Use our interactive measurement tools: - - [SG calculator](/tools/measurement) — calculate specific gravity from hydrostatic weighing - - [Carat estimator](/tools/measurement) — estimate weight from dimensions - - [Hardness reference](/tools/identification) — searchable gem hardness and wearability guide - - [Heavy liquid reference](/tools/lab) — which gems float or sink in standard liquids + - [SG calculator](/tools/measurement) – calculate specific gravity from hydrostatic weighing + - [Carat estimator](/tools/measurement) – estimate weight from dimensions + - [Hardness reference](/tools/identification) – searchable gem hardness and wearability guide + - [Heavy liquid reference](/tools/lab) – which gems float or sink in standard liquids diff --git a/docs/learn/fundamentals/twin-laws.yaml b/docs/learn/fundamentals/twin-laws.yaml index 6f56363..243e57c 100644 --- a/docs/learn/fundamentals/twin-laws.yaml +++ b/docs/learn/fundamentals/twin-laws.yaml @@ -1,5 +1,5 @@ title: Twin Laws in Gemmology -description: Named twin laws — spinel, Carlsbad, Manebach, Baveno, albite, pericline, Brazil, Dauphiné, Japan — and corundum parting, with diagnostic applications. +description: Named twin laws – spinel, Carlsbad, Manebach, Baveno, albite, pericline, Brazil, Dauphiné, Japan – and corundum parting, with diagnostic applications. order: 1.6 category: fundamentals difficulty: advanced @@ -20,7 +20,7 @@ sections: content: | A crystal twin is an intergrowth of two or more crystal individuals of the same species that share some lattice points but have different crystallographic orientations. The geometric - relationship between the parts is defined by the **twin law** — a symmetry operation + relationship between the parts is defined by the **twin law** – a symmetry operation (reflection across a twin plane, or rotation about a twin axis) that is not a symmetry element of the point group of the untwinned crystal. @@ -38,7 +38,7 @@ sections: *Source: Read, P. Gemmology, 3rd ed. DOI: 10.4324/9780080507224 [VERIFIED]* - - title: Spinel Law — Cubic {111} + - title: Spinel Law – Cubic {111} content: | The spinel law is the defining twin law of the cubic system, operating on the {111} octahedral planes. @@ -46,7 +46,7 @@ sections: - **System:** Cubic - **Twin element:** {111} twin plane - **Type:** Contact twin (occasionally polysynthetic as "contact polysynthetic") - - **Recognition feature:** Produces flat, triangular "macle" — an octahedron that appears + - **Recognition feature:** Produces flat, triangular "macle" – an octahedron that appears compressed perpendicular to the {111} plane. The contact face shows a re-entrant notch (triangular depression) where the two individuals meet at the composition surface. - **Gem species:** @@ -58,13 +58,13 @@ sections: callout: type: info - title: Macle — FGA Terminology + title: Macle – FGA Terminology text: | - "Macle" (from French) is the traditional term for a contact twin on the spinel law — a flat, + "Macle" (from French) is the traditional term for a contact twin on the spinel law – a flat, triangular crystal that looks like two octahedra compressed along {111}. The term is used in FGA examination contexts for both spinel and diamond. - - title: Carlsbad, Manebach, and Baveno Laws — Monoclinic Feldspars + - title: Carlsbad, Manebach, and Baveno Laws – Monoclinic Feldspars content: | Three named twin laws apply to monoclinic feldspars (orthoclase, sanidine), distinguished by their twin element and the geometry of the resulting composition surface. @@ -72,7 +72,7 @@ sections: - title: Carlsbad law content: | - **System:** Monoclinic - - **Twin element:** c-axis ([001]) as twin axis — a penetration twin + - **Twin element:** c-axis ([001]) as twin axis – a penetration twin - **Type:** Penetration twin - **Recognition:** Two individuals interpenetrate; the composition surface is irregular and oblique to the long axis of the crystal. Produces a characteristic elongated @@ -83,7 +83,7 @@ sections: - title: Manebach law content: | - **System:** Monoclinic - - **Twin element:** {001} pinacoidal twin plane — contact twin + - **Twin element:** {001} pinacoidal twin plane – contact twin - **Type:** Contact twin - **Recognition:** The {001} pinacoidal cleavage face of orthoclase is also the composition surface. The twin appears as a book-like intergrowth where the cleavage @@ -93,14 +93,14 @@ sections: - title: Baveno law content: | - **System:** Monoclinic - - **Twin element:** {021} twin plane — contact twin + - **Twin element:** {021} twin plane – contact twin - **Type:** Contact twin - **Recognition:** The {021} face produces a re-entrant notch (triangular depression) at the junction of the two individuals. The Baveno law produces a triangular re-entrant angle on the crystal face, distinguishing it from Carlsbad. - **Gem species:** Orthoclase. Also known to occur in some plagioclase. - - title: Albite and Pericline Laws — Triclinic Plagioclase + - title: Albite and Pericline Laws – Triclinic Plagioclase content: | Plagioclase feldspars (albite, oligoclase, labradorite, bytownite, anorthite) are triclinic and characteristically show two simultaneous polysynthetic twin laws that produce the @@ -109,7 +109,7 @@ sections: - title: Albite law content: | - **System:** Triclinic - - **Twin element:** {010} twin plane — polysynthetic contact + - **Twin element:** {010} twin plane – polysynthetic contact - **Type:** Polysynthetic (lamellar) contact twin - **Recognition:** Produces fine parallel striations running across the {001} cleavage face of plagioclase. The striations are perpendicular to the cleavage step edges and @@ -120,7 +120,7 @@ sections: - title: Pericline law content: | - **System:** Triclinic - - **Twin element:** b-axis (the "rhombic section") — polysynthetic penetration + - **Twin element:** b-axis (the "rhombic section") – polysynthetic penetration - **Type:** Polysynthetic penetration twin - **Recognition:** Produces striations on the {010} face at right angles to the albite-law striations. Both laws operate simultaneously in plagioclase, giving a @@ -130,20 +130,20 @@ sections: callout: type: tip - title: Diagnostic Test — Plagioclase vs. Orthoclase + title: Diagnostic Test – Plagioclase vs. Orthoclase text: | Albite-law polysynthetic twinning striations on the {001} cleavage face reliably distinguish plagioclase (striations present) from orthoclase (no striations) without instruments. Use 10× loupe under oblique illumination to see the fine parallel lines. - - title: Brazil Law — Trigonal Quartz (Left/Right Sectors) + - title: Brazil Law – Trigonal Quartz (Left/Right Sectors) content: | - **System:** Trigonal - - **Twin element:** {11̄20} twin plane — polysynthetic penetration twin + - **Twin element:** {11̄20} twin plane – polysynthetic penetration twin - **Type:** Polysynthetic penetration twin - **Recognition:** Sectors of opposite optical handedness (left-handed and right-handed quartz) are intergrown within a single crystal. There is no external morphological - distinction between the two sectors — the twin is invisible optically by normal + distinction between the two sectors – the twin is invisible optically by normal transmitted light. Detection requires: - **Etch figures:** acid etching of the r-face produces triangular etch pits of opposite orientation in left- vs. right-handed sectors. @@ -154,17 +154,17 @@ sections: quartz for piezoelectric use must be twin-free. - **Gem species:** All varieties of quartz (amethyst, citrine, rock crystal, smoky quartz). - - title: Dauphiné Law — Trigonal Quartz (Electrical Twin) + - title: Dauphiné Law – Trigonal Quartz (Electrical Twin) content: | - **System:** Trigonal - - **Twin element:** c-axis (rotation of 60° or 180°) — penetration twin + - **Twin element:** c-axis (rotation of 60° or 180°) – penetration twin - **Type:** Penetration twin - **Recognition:** Dauphiné-law twins are crystallographically rotated by 60° about the c-axis, but this operation is equivalent to a 180° rotation in the point group 32 (the quartz class). They are **indistinguishable externally**: no striations, no colour difference, and no change in RI or birefringence. - - Under the polariscope, Dauphiné twinning causes sector-by-sector anomalous extinction - — different sectors extinguish at slightly different angles, producing an irregular + - Under the polariscope, Dauphiné twinning causes sector-by-sector anomalous extinction; + different sectors extinguish at slightly different angles, producing an irregular "flashing" pattern under crossed polars. This can confuse the gemmologist if not recognised. - The twin does NOT change the optical handedness of the quartz (unlike Brazil law), @@ -174,10 +174,10 @@ sections: term "electrical twin." - **Gem species:** Quartz (common; many quartz crystals contain Dauphiné domains). - - title: Japan Law — Quartz Heart-Shaped Twin + - title: Japan Law – Quartz Heart-Shaped Twin content: | - **System:** Trigonal - - **Twin element:** {11̄22} twin plane — contact twin + - **Twin element:** {11̄22} twin plane – contact twin - **Type:** Contact twin - **Recognition:** Produces a heart-shaped or V-shaped contact twin. The two prism faces of the two individuals meet at a re-entrant angle of approximately 84°, giving the @@ -209,7 +209,7 @@ sections: - title: Recognition of corundum parting content: | On broken corundum rough, parting appears as a series of parallel flat steps (not a - smooth conchoidal fracture curve) at a consistent angle — the {10-11} or {0001} plane. + smooth conchoidal fracture curve) at a consistent angle – the {10-11} or {0001} plane. In faceted stones, parting planes appear as reflective internal planes, sometimes showing interference colour (iridescence), and can be mistaken for cleavage cracks. @@ -217,7 +217,7 @@ sections: - Cutters can split rough along the parting to orient the table perpendicular to the c-axis. - This exploits the parting as a controlled guide plane. - - title: Parting vs cleavage — examination point + - title: Parting vs cleavage – examination point table: headers: - Feature @@ -226,7 +226,7 @@ sections: rows: - ["Cause", "Weak bonding along crystallographic planes inherent to structure", "Twinning lamellae or exsolution planes (not inherent)"] - ["Universality", "Present in all crystals of the species", "Only in crystals that are twinned or have undergone exsolution"] - - ["Corundum", "NONE", "Yes — {10-11} and {0001}"] + - ["Corundum", "NONE", "Yes – {10-11} and {0001}"] - ["Topaz", "{001} perfect cleavage", "Not significant"] - ["Diamond", "{111} perfect octahedral cleavage", "Not significant"] @@ -245,7 +245,7 @@ sections: - **Corundum parting vs cleavage:** stating "corundum has perfect basal cleavage" is a Diploma-level examination error. The correct answer is parting along {0001} and {10-11}. - **Labradorescence:** the polysynthetic albite and pericline twinning lamellae in labradorite - create the thin-film interference responsible for labradorescence — twinning is directly + create the thin-film interference responsible for labradorescence – twinning is directly linked to the phenomenon. - title: Sources diff --git a/docs/learn/identification/treatments-deep/beryllium-diffusion.yaml b/docs/learn/identification/treatments-deep/beryllium-diffusion.yaml index d7a52f3..4b38a41 100644 --- a/docs/learn/identification/treatments-deep/beryllium-diffusion.yaml +++ b/docs/learn/identification/treatments-deep/beryllium-diffusion.yaml @@ -1,4 +1,4 @@ -title: Beryllium Diffusion — Deep Diagnostic Reference +title: Beryllium Diffusion – Deep Diagnostic Reference description: Full per-method detection protocol for beryllium lattice diffusion in corundum, with disclosure standards and stability data. order: 1 category: identification @@ -22,7 +22,7 @@ sections: and fired at **1700–1800 °C** in an oxidising atmosphere for 12–100 hours. Be²⁺ ions (ionic radius 0.27 Å) are small enough to diffuse through the corundum - lattice — unlike Ti or Cr, which remain near-surface. They act as charge compensators + lattice – unlike Ti or Cr, which remain near-surface. They act as charge compensators enabling trapped-hole colour centres (h-Fe: iron paired with oxygen vacancies), producing strong orange/yellow absorption throughout the stone. @@ -43,9 +43,9 @@ sections: (loupe, refractometer, UV lamp, spectroscope). LA-ICP-MS or SIMS is required for a definitive result. Immersion microscopy provides indicative signs only. - - title: Detection — Full Protocol (Loupe to SIMS) + - title: Detection – Full Protocol (Loupe to SIMS) table: - caption: Detection Sequence — Beryllium Diffusion (simplest to most advanced) + caption: Detection Sequence – Beryllium Diffusion (simplest to most advanced) headers: - Method - Finding @@ -53,7 +53,7 @@ sections: - Notes rows: - ["10× loupe / naked eye", "Colour may appear suspiciously homogeneous and intense for the origin; padparadscha oranges from Sri Lanka rarely achieve this saturation naturally", "Indicative only", "Cannot distinguish from plain heat"] - - ["Immersion microscope (40×, dark-field, di-iodomethane)", "In poorly-treated or small stones: slight colour concentration at facet junctions ('spider-web' faint); less pronounced than Ti surface diffusion because penetration is deeper; may appear where facets approach the girdle", "Suggestive — not conclusive", "More reliable for Ti surface diffusion; less reliable for Be"] + - ["Immersion microscope (40×, dark-field, di-iodomethane)", "In poorly-treated or small stones: slight colour concentration at facet junctions ('spider-web' faint); less pronounced than Ti surface diffusion because penetration is deeper; may appear where facets approach the girdle", "Suggestive – not conclusive", "More reliable for Ti surface diffusion; less reliable for Be"] - ["Chelsea Colour Filter", "No specific diagnostic reaction", "Not useful", "Skip in workflow"] - ["UV fluorescence (LWUV/SWUV)", "No reliable discrimination on its own", "Not useful", "Skip in workflow"] - ["LA-ICP-MS (Laser Ablation ICP-MS)", "Be >1–2 ppm in orange/yellow corundum is diagnostic; natural corundum contains <0.1 ppm Be", "Definitive", "Industry standard for lab detection; Emmett et al. 2003 establishes ppm threshold"] @@ -70,7 +70,7 @@ sections: - title: Disclosure Standards content: | - **CIBJO / AGTA**: must be disclosed as a treatment; AGTA code "U" (diffusion) - - **GIA**: reports "lattice diffusion treatment — beryllium present"; NOT acceptable + - **GIA**: reports "lattice diffusion treatment – beryllium present"; NOT acceptable to describe the stone simply as "heated" - **LMHC**: classified as a treatment requiring specific disclosure separate from plain heat treatment (H); coded H(b) or H(Be) on many laboratory reports @@ -88,7 +88,7 @@ sections: - title: Sources content: | - Emmett, J.L. et al. 2003. Beryllium Diffusion of Ruby and Sapphire. *Gems & Gemology*. - DOI: 10.5741/gems.39.2.84 [VERIFIED — live Crossref API confirmed] + DOI: 10.5741/gems.39.2.84 [VERIFIED – live Crossref API confirmed] - Emmett, J.L. et al. 2023. Yellow Sapphire: Natural, Heat-Treated, Beryllium-Diffused, and Synthetic. *Gems & Gemology*. DOI: 10.5741/gems.59.3.268 [VERIFIED] - McClure, S.F. et al. 2010. Gemstone Enhancement and Its Detection in the 2000s. diff --git a/docs/learn/identification/treatments-deep/cvd-diamond.yaml b/docs/learn/identification/treatments-deep/cvd-diamond.yaml index 623da6d..9e2d339 100644 --- a/docs/learn/identification/treatments-deep/cvd-diamond.yaml +++ b/docs/learn/identification/treatments-deep/cvd-diamond.yaml @@ -1,4 +1,4 @@ -title: CVD Diamond Detection — Deep Diagnostic Reference +title: CVD Diamond Detection – Deep Diagnostic Reference description: Full detection protocol for CVD synthetic diamonds, distinguishing from natural and HPHT-treated stones using DiamondView, FTIR, and photoluminescence. order: 4 category: identification @@ -45,20 +45,20 @@ sections: - title: Key CVD Growth Features table: - caption: CVD Diamond — Characteristic Diagnostic Features + caption: CVD Diamond – Characteristic Diagnostic Features headers: - Feature - Description - Origin rows: - - ["SiV⁻ doublet at 736.9/736.6 nm (PL)", "Silicon-vacancy centre from Si contamination in growth chamber; seen in PL at 77 K", "Growth artifact — trace Si in plasma"] + - ["SiV⁻ doublet at 736.9/736.6 nm (PL)", "Silicon-vacancy centre from Si contamination in growth chamber; seen in PL at 77 K", "Growth artifact – trace Si in plasma"] - ["Columnar/striated growth pattern (DiamondView)", "Threads and bundles perpendicular to growth direction; step-flow mechanism produces layered striae", "CVD layer growth architecture"] - ["Orange-red phosphorescence (DiamondView, 225 nm)", "Characteristic phosphorescence not seen in natural diamond or HPHT synthetics (Zhang et al. 2024)", "NV⁻ related; step-flow growth contribution"] - ["NV centres NV⁻ (637 nm) / NV⁰ (575 nm)", "Present in most CVD stones; ratio may differ from HPHT-treated natural diamonds", "N-vacancy pairs in Type IIa lattice"] - ["Type IIa FTIR signature", "No N absorption >5 ppm; NV-H (NVH⁰) at 3123 cm⁻¹ in some samples", "Near-nitrogen-free growth environment"] - ["Anomalous birefringence", "Uniform or banded strain from columnar growth; distinct from natural plastic deformation patterns", "Growth stress in CVD layers"] - - title: Detection Methods — Full Protocol + - title: Detection Methods – Full Protocol table: caption: CVD Diamond Detection (simplest to most advanced) headers: @@ -67,14 +67,14 @@ sections: - Reliability - Notes rows: - - ["LWUV fluorescence (365 nm)", "Variable — inert, orange, or blue depending on post-growth HPHT annealing; anomalous uniformity across the stone", "Preliminary screening", "Cannot confirm CVD alone; triggers lab testing"] + - ["LWUV fluorescence (365 nm)", "Variable – inert, orange, or blue depending on post-growth HPHT annealing; anomalous uniformity across the stone", "Preliminary screening", "Cannot confirm CVD alone; triggers lab testing"] - ["SWUV fluorescence", "Often strong and uniform; lacks the sector fluorescence pattern of HPHT natural diamonds", "Indicative", "Supports but does not confirm CVD"] - - ["DiamondView (225 nm SW UV imaging)", "Orange-red phosphorescence (diagnostic when present); columnar/striated growth — no octahedral sectors; distinct from HPHT cross-hatched sectors", "Most diagnostic single test", "Zhang et al. 2024 is the primary reference for the phosphorescence claim"] - - ["FTIR", "Type IIa signature (N <5 ppm); NV-H absorption at 3123 cm⁻¹ in some CVD samples with N doping", "Instrument test", "Distinguishes Type IIa — necessary but not sufficient for CVD identification alone"] - - ["Photoluminescence at 77 K", "SiV⁻ doublet at 736.9/736.6 nm — characteristic of CVD origin; rarely in natural or HPHT-treated stones; NV⁰ (575 nm) and NV⁻ (637 nm) also present", "Gold-standard lab test", "SiV⁻ doublet is the most specific CVD marker in PL"] + - ["DiamondView (225 nm SW UV imaging)", "Orange-red phosphorescence (diagnostic when present); columnar/striated growth – no octahedral sectors; distinct from HPHT cross-hatched sectors", "Most diagnostic single test", "Zhang et al. 2024 is the primary reference for the phosphorescence claim"] + - ["FTIR", "Type IIa signature (N <5 ppm); NV-H absorption at 3123 cm⁻¹ in some CVD samples with N doping", "Instrument test", "Distinguishes Type IIa – necessary but not sufficient for CVD identification alone"] + - ["Photoluminescence at 77 K", "SiV⁻ doublet at 736.9/736.6 nm – characteristic of CVD origin; rarely in natural or HPHT-treated stones; NV⁰ (575 nm) and NV⁻ (637 nm) also present", "Gold-standard lab test", "SiV⁻ doublet is the most specific CVD marker in PL"] - ["UV-Vis absorption", "Type IIa spectrum; possible 270 nm band if N-doped during growth", "Supporting", "Consistent with Type IIa; not CVD-specific"] - - title: CVD vs HPHT Synthetic vs Natural — Comparison + - title: CVD vs HPHT Synthetic vs Natural – Comparison table: caption: Diamond Type Comparison for Identification headers: diff --git a/docs/learn/identification/treatments-deep/hpht-diamond.yaml b/docs/learn/identification/treatments-deep/hpht-diamond.yaml index ef8816d..9f8454b 100644 --- a/docs/learn/identification/treatments-deep/hpht-diamond.yaml +++ b/docs/learn/identification/treatments-deep/hpht-diamond.yaml @@ -1,4 +1,4 @@ -title: HPHT Diamond Treatment — Deep Diagnostic Reference +title: HPHT Diamond Treatment – Deep Diagnostic Reference description: Full detection protocol for HPHT-treated natural diamonds, including type-by-type outcomes, DiamondView patterns, and photoluminescence signatures. order: 3 category: identification @@ -19,7 +19,7 @@ sections: - title: Process and Conditions content: | High Pressure High Temperature (HPHT) annealing subjects natural diamonds to conditions - of 5–6 GPa pressure and 1700–2100 °C — replicating diamond formation conditions. The + of 5–6 GPa pressure and 1700–2100 °C – replicating diamond formation conditions. The mechanism differs by diamond type. Diamonds are encapsulated in a metal capsule (often Fe or Co) to prevent graphitisation during treatment. @@ -40,7 +40,7 @@ sections: - title: Outcomes by Diamond Type table: - caption: HPHT Treatment — Mechanisms and Results by Type + caption: HPHT Treatment – Mechanisms and Results by Type headers: - Starting Diamond Type - Mechanism @@ -56,7 +56,7 @@ sections: content: | The N3 centre (415 nm, three-nitrogen + vacancy) is responsible for the blue LWUV fluorescence seen in ~80% of natural gem diamonds (type Ia). HPHT-treated type IIa - diamonds frequently show **no blue LWUV fluorescence** — anomalous for gem-quality + diamonds frequently show **no blue LWUV fluorescence** – anomalous for gem-quality colourless stones. This absence is the primary screening trigger. Additional spectroscopic changes: @@ -73,7 +73,7 @@ sections: Hainschwang et al. 2012 (10.5741/gems.48.4.252, [VERIFIED]); Zhu 2024 (10.15506/jog.2024.39.1.24, [VERIFIED]) - - title: Detection Methods — Full Protocol + - title: Detection Methods – Full Protocol table: caption: HPHT Diamond Detection (simplest to most advanced) headers: @@ -82,7 +82,7 @@ sections: - Reliability - Notes rows: - - ["LWUV fluorescence (365 nm)", "Inert / no blue fluorescence in colourless stone — anomalous; ~80% of natural diamonds show at least weak blue", "Primary screening trigger", "Absence of fluorescence alone does not confirm HPHT; triggers lab testing"] + - ["LWUV fluorescence (365 nm)", "Inert / no blue fluorescence in colourless stone – anomalous; ~80% of natural diamonds show at least weak blue", "Primary screening trigger", "Absence of fluorescence alone does not confirm HPHT; triggers lab testing"] - ["Crossed polarisers (microscope)", "Anomalous birefringence: strain patterns, planar annealing fronts, cross-hatched strain halos distinct from untreated type IIa graining", "Strong indicator", "Requires dark-field polarised light microscopy"] - ["FTIR spectroscopy", "Type IIa: no nitrogen absorption (<5 ppm N); 270 nm band absent; 1344 cm⁻¹ isolated-N peak may appear in partially decoloured stones; loss of A-centre peaks", "Instrument test", "Instrument accessible at major labs"] - ["Photoluminescence (PL) at 77 K", "NV⁻/NV⁰ ratio diagnostic; specific centres absent or modified; H3 (503 nm) prominent in some treated types; specialist technique", "Advanced diagnostic", "Hainschwang 2012: NV⁻ 637 nm / NV⁰ 575 nm ratio characteristic"] @@ -108,7 +108,7 @@ sections: **Disclosure:** - Mandatory under CIBJO, AGTA (code HPHT), and all major laboratory standards - GIA practice: "HPHT Processed" laser-inscribed on the girdle (GE POL programme); - all major labs issue treatment notation — no standard grading report without disclosure + all major labs issue treatment notation – no standard grading report without disclosure - LMHC: HPHT treatment is a permanent modification; must be disclosed at every transaction in the supply chain diff --git a/docs/learn/identification/treatments-deep/lead-glass-ruby.yaml b/docs/learn/identification/treatments-deep/lead-glass-ruby.yaml index c8e1ef4..2248d0a 100644 --- a/docs/learn/identification/treatments-deep/lead-glass-ruby.yaml +++ b/docs/learn/identification/treatments-deep/lead-glass-ruby.yaml @@ -1,4 +1,4 @@ -title: Lead Glass-Filled Ruby — Deep Diagnostic Reference +title: Lead Glass-Filled Ruby – Deep Diagnostic Reference description: Full detection protocol for composite (lead glass-filled) ruby, with nomenclature, durability, and disclosure standards. order: 2 category: identification @@ -31,7 +31,7 @@ sections: include cobalt oxide to add blue tinting to mask brownish or orange body tones. callout: type: error - title: Composite Ruby — Not a Treated Ruby + title: Composite Ruby – Not a Treated Ruby text: | Stones containing significant glass fill are composite materials, not treated rubies. CIBJO and GIA require the term "composite ruby" or "glass-filled ruby". The term @@ -42,7 +42,7 @@ sections: - title: Physical Properties of Composite Ruby table: - caption: Composite Ruby vs Natural Ruby — Physical Comparison + caption: Composite Ruby vs Natural Ruby – Physical Comparison headers: - Property - Natural Ruby @@ -54,7 +54,7 @@ sections: - ["UV fluorescence (SWUV)", "Variable red/orange Cr fluorescence", "Glass may fluoresce chalky greenish"] - ["Acid resistance", "Unaffected by dilute acid", "Glass etched and clouded by lemon juice or HCl"] - - title: Detection Methods — Full Protocol + - title: Detection Methods – Full Protocol table: caption: Lead Glass-Filled Ruby Detection (simplest to most advanced) headers: @@ -64,14 +64,14 @@ sections: - Notes rows: - ["10× loupe, reflected light", "Glassy/vitreous lustre patches interrupting ruby's adamantine lustre; depressions or pits where glass has eroded", "Strong indicator", "Most accessible first check"] - - ["Darkfield microscope (40–60×) — blue/orange flash", "Blue flash when tilted one way, orange flash the other, at fracture–ruby interface (thin-film interference from glass fill–corundum boundary)", "Most reliable in-lab indicator", "Primary diagnostic; described in McClure et al. 2006"] - - ["Gas bubbles (40–60×, darkfield)", "Spherical or elongated bubbles trapped in glass fill — not present in natural growth features (feathers, fingerprints)", "Diagnostic", "Natural features never contain spherical bubbles"] + - ["Darkfield microscope (40–60×) – blue/orange flash", "Blue flash when tilted one way, orange flash the other, at fracture–ruby interface (thin-film interference from glass fill–corundum boundary)", "Most reliable in-lab indicator", "Primary diagnostic; described in McClure et al. 2006"] + - ["Gas bubbles (40–60×, darkfield)", "Spherical or elongated bubbles trapped in glass fill – not present in natural growth features (feathers, fingerprints)", "Diagnostic", "Natural features never contain spherical bubbles"] - ["Flow structures (40–60×)", "Swirling patterns in glass under darkfield; absent in natural feathers and liquid inclusions", "Diagnostic", "Confirms glass rather than resin"] - ["Hydrostatic SG", "Values <3.90 in a ruby-sized stone strongly suggest significant glass content", "Strong screening", "Natural ruby ~4.00; composite values as low as 3.60"] - ["Chelsea Colour Filter (cobalt variant)", "If cobalt in glass: red reaction from Co; combined glass-fill + cobalt gives anomalous result vs pure Cr ruby", "Useful if cobalt glass suspected", "Natural ruby reacts red from Cr only"] - ["SW UV fluorescence", "Lead glass frequently fluoresces chalky greenish or shows abnormal fluorescence patterns not seen in natural ruby inclusions", "Supporting", "Not conclusive alone"] - - ["Acid sensitivity test (destructive)", "A drop of lemon juice (citric acid, pH ~2) or dilute HCl on pavilion girdle: glass etches and clouds within minutes; corundum unaffected", "Conclusive if positive", "Destructive — use only on obscure area, when other evidence inconclusive"] - - ["EDXRF", "Elevated Pb signal at surface or in fractures — Pb is diagnostic of glass fill; non-destructive, rapid", "Definitive confirmation", "Most labs use EDXRF as first confirmatory step"] + - ["Acid sensitivity test (destructive)", "A drop of lemon juice (citric acid, pH ~2) or dilute HCl on pavilion girdle: glass etches and clouds within minutes; corundum unaffected", "Conclusive if positive", "Destructive – use only on obscure area, when other evidence inconclusive"] + - ["EDXRF", "Elevated Pb signal at surface or in fractures – Pb is diagnostic of glass fill; non-destructive, rapid", "Definitive confirmation", "Most labs use EDXRF as first confirmatory step"] - ["LA-ICP-MS", "Quantifies Pb at trace and major element levels; unambiguous confirmation of glass fill", "Definitive", "Used in research-level reports"] - title: Disclosure and Nomenclature @@ -85,12 +85,12 @@ sections: "enhanced ruby" is considered insufficient; correct terminology is "glass-filled composite ruby" - **Gem-A**: distinction between "treated ruby" (heated, oiled) and "glass-filled - composite ruby" is categorically important — these are different disclosure situations + composite ruby" is categorically important – these are different disclosure situations and different value categories - title: Stability and Care table: - caption: Lead Glass-Filled Ruby — Care Warnings + caption: Lead Glass-Filled Ruby – Care Warnings headers: - Risk Factor - Effect diff --git a/docs/learn/identification/treatments.yaml b/docs/learn/identification/treatments.yaml index edc057b..5657e5a 100644 --- a/docs/learn/identification/treatments.yaml +++ b/docs/learn/identification/treatments.yaml @@ -1,5 +1,5 @@ title: Gemstone Treatments -description: Heat treatment, filling, diffusion, coating, and detection methods for treated gemstones — with per-species diagnostic depth. +description: Heat treatment, filling, diffusion, coating, and detection methods for treated gemstones – with per-species diagnostic depth. order: 5 category: identification difficulty: intermediate @@ -55,16 +55,16 @@ sections: subsections: - title: Diagnostic Inclusion Changes (Darkfield 40–60×) content: | - - **Dissolved silk** — rutile needles partially resorbed; appear as dotted trails + - **Dissolved silk** – rutile needles partially resorbed; appear as dotted trails or "fingerprint" remnants along former needle orientation; diagnostic for heat above 1400 °C - - **Discoid (halo) fractures** — disc-shaped stress fractures around zircon, + - **Discoid (halo) fractures** – disc-shaped stress fractures around zircon, apatite, or calcite inclusions from thermal expansion; highly diagnostic for heat above 1600 °C - - **Flux residue droplets** — colourless rounded glass blebs at fracture mouths + - **Flux residue droplets** – colourless rounded glass blebs at fracture mouths (borax); show anomalous birefringence under crossed polars; diagnostic for H(a) flux-healing treatment - - **Partially healed fractures** — feathered, partially recrystallised fractures + - **Partially healed fractures** – feathered, partially recrystallised fractures with residual fluid inclusions; distinct from natural growth features - title: FTIR Evidence for Unheated Sapphire @@ -86,7 +86,7 @@ sections: - "No evidence of heat treatment" (NTE) on a laboratory report commands a significant premium; verify by the inclusion criteria above - - title: Beryllium Diffusion — Lattice Diffusion (Sapphire) + - title: Beryllium Diffusion – Lattice Diffusion (Sapphire) content: | Commercialised around 2001. Beryllium (Be²⁺) ions diffuse through the full corundum lattice at 1700–1800 °C producing intense orange, yellow, or padparadscha colours. @@ -99,14 +99,14 @@ sections: LA-ICP-MS or SIMS is required for a definitive result. All corundum sold as padparadscha or vivid-orange sapphire should carry a laboratory report. - Full detection protocol: see Deep Reference — Beryllium Diffusion. + Full detection protocol: see Deep Reference – Beryllium Diffusion. subsections: - title: Process Overview content: | Rough is packed in BeO or chrysoberyl powder and fired at 1700–1800 °C in an oxidising atmosphere for 12–100 hours. Be²⁺ (ionic radius 0.27 Å) penetrates the full lattice, unlike Ti or Cr which remain within ~50–100 µm of the surface. - Colour is **lattice-deep** — re-cutting does not remove it. + Colour is **lattice-deep** – re-cutting does not remove it. Sources: Emmett et al. 2003 (10.5741/gems.39.2.84, [VERIFIED]); Emmett et al. 2023 (10.5741/gems.59.3.268, [VERIFIED]) @@ -114,20 +114,20 @@ sections: - title: Key Detection Points content: | - **10× loupe**: colour may appear suspiciously homogeneous; immersion spider-web - is faint (if present) — less pronounced than Ti surface diffusion + is faint (if present) – less pronounced than Ti surface diffusion - **LA-ICP-MS**: Be >1–2 ppm in orange/yellow corundum is diagnostic; natural corundum contains <0.1 ppm Be - **SIMS**: diffusion gradient (high at surface, declining inward) confirms treatment - **Stability**: permanent; colour survives repolishing, ultrasonic, and steam - - **Disclosure**: AGTA code U; GIA reports "lattice diffusion — beryllium present" + - **Disclosure**: AGTA code U; GIA reports "lattice diffusion – beryllium present" - - title: Surface Diffusion vs Lattice Diffusion — The Depth Distinction + - title: Surface Diffusion vs Lattice Diffusion – The Depth Distinction content: | The critical diagnostic difference between titanium surface diffusion (Ti, pre-2001, now rare) and beryllium lattice diffusion is colour penetration depth and the resulting immersion microscopy appearance. table: - caption: Surface vs Lattice Diffusion — Key Differences + caption: Surface vs Lattice Diffusion – Key Differences headers: - Property - Ti Surface Diffusion @@ -144,7 +144,7 @@ sections: content: | Immerse the stone in di-iodomethane (or water) and observe under darkfield illumination at 40–60× magnification. In titanium surface-diffused sapphire, colour accumulates as - a visible network following facet edges — the "spider-web". Where two surfaces meet, + a visible network following facet edges – the "spider-web". Where two surfaces meet, the diffused zone doubles in thickness and appears darker. Scratches, chips, or abrasions on facets will expose colourless material beneath. @@ -166,17 +166,17 @@ sections: - Finding rows: - ["10× loupe, reflected light", "Lustre difference at fracture mouths; slightly vitreous vs adamantine"] - - ["Darkfield microscope (40×) — flash effect", "Orange/yellowish-orange iridescent flash at filler–crystal interface when tilted (primary in-lab test)"] + - ["Darkfield microscope (40×) – flash effect", "Orange/yellowish-orange iridescent flash at filler–crystal interface when tilted (primary in-lab test)"] - ["Gas bubbles / flow structures", "Spherical bubbles or swirling patterns in polymer; absent in natural fluid inclusions"] - ["UV fluorescence (LWUV/SWUV)", "Opticon and resins: chalky-blue or yellowish-green glow; cedar oil: negligible fluorescence"] - - ["FTIR spectroscopy", "Resins: C–H stretching ~3000–3050 cm⁻¹; C=O stretching ~1700–1730 cm⁻¹; unfilled emerald shows no organic absorptions — definitive"] + - ["FTIR spectroscopy", "Resins: C–H stretching ~3000–3050 cm⁻¹; C=O stretching ~1700–1730 cm⁻¹; unfilled emerald shows no organic absorptions – definitive"] Source: Kammerling et al. 1991 (10.5741/gems.27.2.70, [VERIFIED]) - title: LMHC Fracture-Fill Disclosure Scale content: | The Laboratory Manual Harmonisation Committee (LMHC) has established a harmonised - grading scale for emerald fracture filling [PARTIALLY_SUPPORTED — institutional document; + grading scale for emerald fracture filling [PARTIALLY_SUPPORTED – institutional document; not API-retrievable as peer-reviewed paper; cite via https://www.lmhc-gemmology.org]: - **F1 (None)**: no filler; unfilled stone @@ -197,23 +197,23 @@ sections: - title: Lead Glass-Filled Ruby (Composite Ruby) callout: type: error - title: Composite Ruby — Distinct from Treated Ruby + title: Composite Ruby – Distinct from Treated Ruby text: | Heavily fractured low-quality corundum filled with high-lead-content glass (PbO 70–95%) is a composite material. CIBJO and GIA require the term "composite ruby" or "glass-filled - ruby" — not "treated ruby" or "enhanced ruby". Stones can contain more glass than ruby. + ruby" – not "treated ruby" or "enhanced ruby". Stones can contain more glass than ruby. Damage agents: jeweller's torch, dilute acids (lemon juice), ultrasonic, steam. - Full detection protocol: see Deep Reference — Lead Glass-Filled Ruby. + Full detection protocol: see Deep Reference – Lead Glass-Filled Ruby. subsections: - title: Key Properties and Detection Summary content: | - **SG**: depressed from natural ruby ~4.00 to composite values as low as 3.60–3.80 - **Blue/orange flash effect** (darkfield, 40–60×): vivid blue flash one way, orange - flash the other, at the glass–ruby interface — the most reliable in-lab indicator + flash the other, at the glass–ruby interface – the most reliable in-lab indicator - **Gas bubbles**: spherical bubbles in glass fill; never in natural growth features - - **SW UV**: lead glass fluoresces chalky greenish — abnormal for ruby inclusions + - **SW UV**: lead glass fluoresces chalky greenish – abnormal for ruby inclusions - **EDXRF**: elevated Pb at surface is diagnostic; non-destructive, rapid - **Acid test (destructive)**: lemon juice etches glass within minutes; corundum unaffected @@ -223,18 +223,18 @@ sections: content: | HPHT annealing (5–6 GPa, 1700–2100 °C) can decolourise brown Type IIa diamonds to near-colourless (D–H) or create fancy colours in other types. Cannot be detected by - standard tools — laboratory testing is required. + standard tools – laboratory testing is required. callout: type: info title: Deep Reference Available text: | Full detection protocol, type-by-type outcome table, DiamondView pattern comparison, - and photoluminescence signature detail: see Deep Reference — HPHT Diamond Treatment. + and photoluminescence signature detail: see Deep Reference – HPHT Diamond Treatment. subsections: - title: Key Signatures content: | - **Absent LWUV blue fluorescence**: ~80% of natural gem diamonds show blue LWUV; - HPHT-treated type IIa are typically inert — primary screening trigger + HPHT-treated type IIa are typically inert – primary screening trigger - **FTIR**: type IIa signature (no N >5 ppm); 270 nm brown absorption absent after treatment; 1344 cm⁻¹ isolated-N peak may appear in partially decoloured stones - **DiamondView**: cross-hatched or irregular green sectors (modified octahedral growth); @@ -256,14 +256,14 @@ sections: title: Deep Reference Available text: | Full detection protocol, comparison table (CVD vs HPHT vs natural), secondary HPHT - complication note, and citation for orange-red phosphorescence: see Deep Reference — + complication note, and citation for orange-red phosphorescence: see Deep Reference – CVD Diamond Detection. subsections: - title: Key Diagnostic Features content: | - **DiamondView (225 nm SW UV)**: orange-red phosphorescence (diagnostic when present); - columnar/striated growth threads — no octahedral growth sectors - (Zhang et al. 2024, 10.3390/cryst14090804, [VERIFIED] — resolves VERIFIED.md F-03 flag) + columnar/striated growth threads – no octahedral growth sectors + (Zhang et al. 2024, 10.3390/cryst14090804, [VERIFIED] – resolves VERIFIED.md F-03 flag) - **PL at 77 K**: SiV⁻ doublet at 736.9/736.6 nm characteristic of CVD growth; rarely present in natural or HPHT-treated stones - **FTIR**: Type IIa signature; NV-H (3123 cm⁻¹) in some N-doped CVD samples @@ -286,7 +286,7 @@ sections: visible through the nacre. The radiation also denatures conchiolin, detectable by ESR. **ESR (Electron Spin Resonance)** detects the CO₂⁻ radical (g-factor 2.001 ± 0.002) - from radiation damage to carbonate — the gold-standard diagnostic for irradiation. + from radiation damage to carbonate – the gold-standard diagnostic for irradiation. **LWUV fluorescence**: irradiated Akoya show no/very weak fluorescence (radiation damages conchiolin fluorophore); natural black Tahitian show reddish-pink/red glow. **EDXRF**: elevated Ag = silver-nitrate dye; Mn/Fe nucleus profiling for irradiation. @@ -299,7 +299,7 @@ sections: content: | Pearls are immersed in AgNO₃ solution then exposed to H₂S gas or sunlight, precipitating Ag₂S (silver sulphide) in the nacre layers, producing blue-grey to - black colour. [PARTIALLY_SUPPORTED — Ag₂S mechanism is established trade knowledge; + black colour. [PARTIALLY_SUPPORTED – Ag₂S mechanism is established trade knowledge; the specific precipitation chemistry details are not independently confirmed to peer-reviewed paper level at this time; present as trade knowledge.] @@ -366,7 +366,7 @@ sections: (Physical Vapour Deposition) at low temperatures. The multilayer interference film produces vivid iridescent "rainbow" colours varying with viewing angle. - [PARTIALLY_SUPPORTED — mystic topaz TiO₂/SiO₂ multilayer PVD specifics are from industry + [PARTIALLY_SUPPORTED – mystic topaz TiO₂/SiO₂ multilayer PVD specifics are from industry literature; Shigley et al. 2012 (10.5741/gems.48.1.18, [VERIFIED]) confirms the detection principle and coated gem methodology via study of coated CZ (Diamantine).] subsections: @@ -376,9 +376,9 @@ sections: - **10× loupe**: visible chipping or abrasion at facet junctions; underlying colourless topaz visible through scratches - **Angle-dependent colour shift**: colour pattern shifts predictably with angle - (thin-film interference) — different from random play-of-colour of precious opal + (thin-film interference) – different from random play-of-colour of precious opal - **Acetone swab (cautious, on pavilion)**: some coatings lift on contact - - **EDXRF**: anomalous Ti, Nb, or Si at the surface — topaz itself contains neither + - **EDXRF**: anomalous Ti, Nb, or Si at the surface – topaz itself contains neither **Stability:** - Poor wear resistance; coating hardness lower than topaz (Mohs 8); @@ -403,7 +403,7 @@ sections: - title: Quench-Crackling of Quartz callout: type: info - title: Confidence C — Citation Gap + title: Confidence C – Citation Gap text: | The process and detection features below are from established gemmological teaching material (consistent with Read 7th ed. and Gem-A textbooks). No peer-reviewed @@ -419,7 +419,7 @@ sections: - title: Detection content: | - **10× loupe**: dense, uniform, pervasive fracture network with no preferred - crystallographic orientation — diagnostic; contrast with sparse, irregular, + crystallographic orientation – diagnostic; contrast with sparse, irregular, curved natural quartz fractures - **Transmitted light**: dye visible only in fractures; quartz crystals between fractures remain colourless; no natural quartz variety has colour only in fractures @@ -428,7 +428,7 @@ sections: quartz shows no organic absorptions This material is an imitation/simulation: CIBJO requires "dyed crackled quartz" - or "quench-crackled quartz" — not a natural quartz variety designation. + or "quench-crackled quartz" – not a natural quartz variety designation. - title: Treatment Acceptance Summary comparison: @@ -442,10 +442,10 @@ sections: - title: Accepted with Full Disclosure variant: warning points: - - Resin filling (polymer) — emerald + - Resin filling (polymer) – emerald - Beryllium lattice diffusion - Irradiation (most types) - - HPHT diamond (permanent — must disclose) + - HPHT diamond (permanent – must disclose) - title: Controversial / Explicit Disclosure Required variant: danger points: @@ -463,7 +463,7 @@ sections: - Sensitive To - Care Notes rows: - - ["Heat (corundum — plain H)", "Permanent", "N/A", "No special care needed"] + - ["Heat (corundum – plain H)", "Permanent", "N/A", "No special care needed"] - ["Flux heating H(a)", "Permanent colour; flux residues stable", "N/A", "Disclose separately from plain H"] - ["Heat (zircon)", "Stable", "Extreme heat", "Avoid jeweller's torch"] - ["Oil (emerald)", "Temporary", "Heat, solvents, time", "Re-oil periodically; no ultrasonic"] @@ -501,7 +501,7 @@ sections: rows: - ["N or NTE", "No treatment evidence", "No indication of any treatment"] - ["H", "Heat treatment", "Evidence of heating detected"] - - ["H(a)", "Heat with flux residue / fracture healing", "Borax or similar flux — disclosed separately from plain H"] + - ["H(a)", "Heat with flux residue / fracture healing", "Borax or similar flux – disclosed separately from plain H"] - ["H(b) or H(Be)", "Beryllium diffusion", "Lattice diffusion; LA-ICP-MS required"] - ["O(minor)", "Minor oil", "Light oiling; typical for emerald"] - ["O(moderate)", "Moderate oil", "Moderate enhancement; requires disclosure"] @@ -513,11 +513,11 @@ sections: - title: Key Report Phrases content: | - - **"No indication of heat treatment"** — stone appears unheated; high commercial value - - **"Lattice diffusion treatment — beryllium present"** — Be-diffusion; not plain heating - - **"Composite ruby"** — glass-filled composite; not a standard ruby report - - **"HPHT Processed"** — diamond colour modified by HPHT treatment - - **"Filler detected"** — fracture filling present; type will be specified + - **"No indication of heat treatment"** – stone appears unheated; high commercial value + - **"Lattice diffusion treatment – beryllium present"** – Be-diffusion; not plain heating + - **"Composite ruby"** – glass-filled composite; not a standard ruby report + - **"HPHT Processed"** – diamond colour modified by HPHT treatment + - **"Filler detected"** – fracture filling present; type will be specified - title: Trade Organisation Standards subsections: diff --git a/docs/learn/market/grading-valuation.yaml b/docs/learn/market/grading-valuation.yaml index 3306ca8..7e6f974 100644 --- a/docs/learn/market/grading-valuation.yaml +++ b/docs/learn/market/grading-valuation.yaml @@ -21,7 +21,7 @@ sections: content: | Grading coloured gemstones is more complex than grading diamonds because there is no universal standard system. The "4 Cs" (Colour, Clarity, Cut, Carat weight) apply, but - colour is overwhelmingly the most important factor—often accounting for 50-70% of + colour is overwhelmingly the most important factor – often accounting for 50-70% of a coloured stone's value. Professional grading requires controlled lighting conditions, master stones for diff --git a/docs/learn/origin/afghanistan/emerald.yaml b/docs/learn/origin/afghanistan/emerald.yaml index dd8f670..303df35 100644 --- a/docs/learn/origin/afghanistan/emerald.yaml +++ b/docs/learn/origin/afghanistan/emerald.yaml @@ -1,4 +1,4 @@ -title: Panjshir Emerald — Afghanistan +title: Panjshir Emerald – Afghanistan description: Hydrothermal-sediment hosted Panjshir emerald; high Fe UV-Vis bands, low Li, three-phase inclusions in black shale context; distinction from Colombian. order: 3 category: origin @@ -25,7 +25,7 @@ sections: Panjshir Valley emerald (Parwan/Kapisa Province, Afghanistan) has been mined since at least the 19th century but gained systematic international attention after the Soviet withdrawal; Bowersox et al. (1991) provided the first systematic gemological - description. The deposit is hydrothermally hosted in black shales and phyllites — + description. The deposit is hydrothermally hosted in black shales and phyllites – a sediment-hosted type genetically different from Colombian black-shale (no igneous proximity) and from ophiolite-hosted Swat emeralds. The Panjshir is one of the few major emerald sources without associated igneous rocks nearby. @@ -34,7 +34,7 @@ sections: content: | Panjshir emerald genesis: - - **Host rock**: Hydrothermal veins in black shales and phyllites — the "sediment- + - **Host rock**: Hydrothermal veins in black shales and phyllites – the "sediment- hosted" model; unlike Colombian black-shale type, Panjshir lacks documented proximal igneous rocks as the Be/Cr source - **Formation**: Hydrothermal fluids exploited fracture systems in the organic-rich @@ -58,7 +58,7 @@ sections: - title: Chromophores content: | - Cr³⁺ (primary); some V³⁺; Fe (as chromophore and fluorescence quencher) - - The Fe spectral bands are a key analytical criterion — much stronger than + - The Fe spectral bands are a key analytical criterion – much stronger than in Colombian material - title: Trace Element Chemistry @@ -76,7 +76,7 @@ sections: content: | - **UV-Vis iron bands**: Panjshir shows "pronounced iron-related bands" not typical of Colombian emerald, which is Fe-poor and therefore shows - stronger red fluorescence — the UV-Vis spectral difference is a primary + stronger red fluorescence – the UV-Vis spectral difference is a primary analytical criterion - **Alkali elements, Sc, Mn, Co, Ni, Zn, Ga**: Multivariate trace element patterns provide further discrimination; laboratory LA-ICP-MS required @@ -104,8 +104,8 @@ sections: - Colombian Muzo - Swat (Pakistan) rows: - - ["Three-phase inclusions", "Present (varies)", "Yes — with halite cube", "Yes (documented)"] - - ["Parisite crystals", "Absent", "Diagnostic — present", "Absent"] + - ["Three-phase inclusions", "Present (varies)", "Yes – with halite cube", "Yes (documented)"] + - ["Parisite crystals", "Absent", "Diagnostic – present", "Absent"] - ["Host context clues", "Black shale carbon", "Albite + calcite", "Chromian muscovite"] - ["Fe bands in UV-Vis", "Pronounced", "Absent/minimal", "Moderate"] - ["Li content", "<200 ppmw", "<200 ppmw", "<200 ppmw"] diff --git a/docs/learn/origin/afghanistan/lapis.yaml b/docs/learn/origin/afghanistan/lapis.yaml index 62a6825..88bc6b1 100644 --- a/docs/learn/origin/afghanistan/lapis.yaml +++ b/docs/learn/origin/afghanistan/lapis.yaml @@ -1,5 +1,5 @@ -title: Lapis Lazuli — Sar-e-Sang, Afghanistan -description: Sar-e-Sang (Badakhshan) lapis lazuli — the canonical ancient-world source, >7,000 years of continuous mining, geochemical fingerprinting, grades and quality. +title: Lapis Lazuli – Sar-e-Sang, Afghanistan +description: Sar-e-Sang (Badakhshan) lapis lazuli – the canonical ancient-world source, >7,000 years of continuous mining, geochemical fingerprinting, grades and quality. order: 2 category: origin subcategory: afghanistan @@ -21,11 +21,11 @@ sections: - title: Introduction content: | The Sar-e-Sang deposit in the Kokcha River Valley of Badakhshan Province, Afghanistan, - is the world's oldest continuously operated gem mine — mined for more than 7,000 years + is the world's oldest continuously operated gem mine – mined for more than 7,000 years without interruption. It supplied lapis lazuli to the pharaohs of Egypt, the scribes of Mesopotamia, and the craftspeople of the Indus Valley civilisation. Lo Giudice et al. (2016) demonstrated through geochemical provenance protocols that ancient artefacts - from Egyptian museums were of "Afghan origin" — confirming the singular historical + from Egyptian museums were of "Afghan origin" – confirming the singular historical primacy of this deposit. - title: Mineralogy of Lapis Lazuli @@ -38,7 +38,7 @@ sections: a member of the sodalite group containing sulfur as S₃⁻ chromophore - **Calcite**: White to colourless; determines the grade (less calcite = higher grade in the Sar-e-Sang system) - - **Pyrite**: Gold metallic flecks — characteristic and commercially valued + - **Pyrite**: Gold metallic flecks – characteristic and commercially valued in Afghan material - **Minor minerals**: Diopside, phlogopite, wollastonite from the contact metamorphic environment @@ -46,7 +46,7 @@ sections: - title: Colour Mechanism content: | - The blue colour arises from the S₃⁻ radical anion (trisulfide) in the - lazurite structure — the same mechanism responsible for ultramarine pigment + lazurite structure – the same mechanism responsible for ultramarine pigment produced synthetically since the 19th century - Cu/Fe ratio in the broader mineral assemblage and S₃⁻ concentration control the exact tone: deeper blue with higher S₃⁻ @@ -80,7 +80,7 @@ sections: type: info title: The Gold Flecks text: | - The gold-coloured metallic flecks in lapis lazuli are PYRITE (FeS₂) — iron + The gold-coloured metallic flecks in lapis lazuli are PYRITE (FeS₂) – iron sulfide. In Afghan Sar-e-Sang material, evenly distributed fine pyrite flecks are considered a quality feature, indicating a natural, untreated stone from the metamorphic contact zone. @@ -119,7 +119,7 @@ sections: Sar-e-Sang lapis imported via the Silk Road - The Sanskrit word for blue (nila) and the Persian word for lapis (lazhward) both derive from the cultural centrality of this material - - The mine has been operated under continuous human control for 70+ centuries — + - The mine has been operated under continuous human control for 70+ centuries – arguably the longest-operating mine in human history sources: diff --git a/docs/learn/origin/afghanistan/overview.yaml b/docs/learn/origin/afghanistan/overview.yaml index c0fa2c5..c105058 100644 --- a/docs/learn/origin/afghanistan/overview.yaml +++ b/docs/learn/origin/afghanistan/overview.yaml @@ -1,5 +1,5 @@ -title: Afghanistan — Gem Origins Overview -description: Hindu Kush gem province — lapis lazuli (Sar-e-Sang), Panjshir emerald, Nuristan kunzite; multiple geological settings; conflict and artisanal mining context. +title: Afghanistan – Gem Origins Overview +description: Hindu Kush gem province – lapis lazuli (Sar-e-Sang), Panjshir emerald, Nuristan kunzite; multiple geological settings; conflict and artisanal mining context. order: 1 category: origin subcategory: afghanistan @@ -26,7 +26,7 @@ sections: content: | Afghanistan sits at the convergence of the Hindu Kush, Pamir, and Karakoram ranges and hosts some of the world's most historically significant gem deposits. The Sar-e-Sang - lapis lazuli mines in Badakhshan are the canonical ancient-world lapis source — mined + lapis lazuli mines in Badakhshan are the canonical ancient-world lapis source – mined continuously for more than 7,000 years and supplying Egypt, Mesopotamia, and the Indus Valley civilisations. Panjshir Valley emerald and Nuristan kunzite complete a portfolio that makes Afghanistan a geologically extraordinary gem province. @@ -40,7 +40,7 @@ sections: rows: - ["Sar-e-Sang, Badakhshan", "Contact-metasomatic marble (ancient plutonic belt)", "Lapis lazuli"] - ["Panjshir Valley", "Hydrothermal veins in black shales/phyllites", "Emerald"] - - ["Jagdalak, Kabul Province", "Marble-hosted corundum", "Ruby [CITATION NEEDED — see note]"] + - ["Jagdalak, Kabul Province", "Marble-hosted corundum", "Ruby [CITATION NEEDED – see note]"] - ["Nuristan / Kunar", "LCT granite pegmatites", "Kunzite, tourmaline, aquamarine"] - title: Mining Under Conflict @@ -57,7 +57,7 @@ sections: fragmented. International gem laboratories increasingly receive Afghan-origin material for origin certification, requiring careful chain-of-custody documentation. - - title: Nuristan — Kunzite and Pegmatite Gems + - title: Nuristan – Kunzite and Pegmatite Gems content: | Nuristan Province and adjacent Kunar Province host one of the world's finest sources of gem kunzite (pink-lilac spodumene, LiAlSi₂O₆, Mn-coloured) in @@ -66,13 +66,13 @@ sections: - Green tourmaline (elbaite) - Aquamarine (blue-green beryl) - Rubellite (red tourmaline) - - Hiddenite (green spodumene — rare) + - Hiddenite (green spodumene – rare) Afghan kunzite crystals are among the largest and most saturated in the trade. No dedicated origin-determination paper for Nuristan kunzite specifically was retrieved; this material is identified by physical properties and geological provenance. - - title: Jagdalak Ruby — Citation Note + - title: Jagdalak Ruby – Citation Note callout: type: warning title: CITATION NEEDED diff --git a/docs/learn/origin/brazil-additional.yaml b/docs/learn/origin/brazil-additional.yaml index 67b0a25..9fd3e86 100644 --- a/docs/learn/origin/brazil-additional.yaml +++ b/docs/learn/origin/brazil-additional.yaml @@ -1,4 +1,4 @@ -title: Brazil — Imperial Topaz and Emerald Sub-distinctions +title: Brazil – Imperial Topaz and Emerald Sub-distinctions description: Ouro Preto imperial topaz (Cr-coloured, strong LWUV fluorescence); Itabira vs Carnaíba emerald distinction (Cr vs V dominant, inclusion differences). Cross-reference brazil/ folder. order: 7 category: origin @@ -30,7 +30,7 @@ sections: Imperial topaz from Ouro Preto is covered here as the only Cr-coloured commercial topaz in Brazil. - - title: Imperial Topaz — Ouro Preto, Minas Gerais + - title: Imperial Topaz – Ouro Preto, Minas Gerais content: | The defining Brazilian imperial topaz deposit: subsections: @@ -48,13 +48,13 @@ sections: - title: Colour and Chromophore content: | - **Colour range**: Yellow-orange (sherry), gold, pinkish-orange (peach), - pink-orange, orange-pink; rarely pure pink — a continuous warm spectrum + pink-orange, orange-pink; rarely pure pink – a continuous warm spectrum - **Chromophore**: Cr³⁺ in trace quantities contributes to the colour; colour centres from natural irradiation may also contribute - Da Costa et al. (2000) identified chromium-related character; some debate remains on the relative contribution of Cr vs colour centres; the pink modifier in the most prized stones is believed Cr-related - [PARTIALLY_SUPPORTED — not fully established in peer-reviewed record] + [PARTIALLY_SUPPORTED – not fully established in peer-reviewed record] - title: Properties content: | @@ -62,7 +62,7 @@ sections: - **RI**: 1.619–1.627 (α), 1.620–1.628 (β), 1.627–1.636 (γ); birefringence: 0.008–0.010 - **SG**: 3.49–3.57; Hardness: 8 (Mohs) - - **Fluorescence (LWUV)**: Strong yellow-orange to orange — one of the + - **Fluorescence (LWUV)**: Strong yellow-orange to orange – one of the strongest fluorescences of any gem topaz; a key identification aid - **Absorption**: Weak Cr bands (~630–680 nm) in some stones @@ -95,9 +95,9 @@ sections: subsections: - title: Itabira / Nova Era Type (Minas Gerais) content: | - - **Location**: Nova Era, Itabira, Belém do Cruzeio — all Minas Gerais + - **Location**: Nova Era, Itabira, Belém do Cruzeio – all Minas Gerais - **Geological setting**: Talc-chlorite-carbonate schist at the contact between - Proterozoic quartzites and ultramafic bodies — "schist-belt" type, analogous + Proterozoic quartzites and ultramafic bodies – "schist-belt" type, analogous to Sandawana (Zimbabwe) and Shakiso (Ethiopia) - **Chromophore**: Cr³⁺ + moderate V³⁺; low Fe content - **Colour**: Vivid green; comparable to Sandawana quality but achievable at @@ -111,12 +111,12 @@ sections: - **Location**: Carnaíba and Socotó, Bahia State, northeastern Brazil - **Geological setting**: Talc-carbonate veins cutting ultramafic rocks of the Carnaíba ultramafite complex - - **Chromophore**: Predominantly V³⁺ with lower Cr — similar to Colombian + - **Chromophore**: Predominantly V³⁺ with lower Cr – similar to Colombian Chivor material in Cr/V profile - **Fe content**: Slightly higher than Itabira - **Colour**: Slightly "colder" green than the Cr-dominant Itabira type; less warm, sometimes more yellowish-green - - **Inclusions**: Talc plates (distinctive — soft, platy; from ultramafic host); + - **Inclusions**: Talc plates (distinctive – soft, platy; from ultramafic host); two-phase fluid inclusions; phlogopite - title: Itabira vs Carnaíba Comparison diff --git a/docs/learn/origin/burma/ruby.yaml b/docs/learn/origin/burma/ruby.yaml index 3991b12..bef755d 100644 --- a/docs/learn/origin/burma/ruby.yaml +++ b/docs/learn/origin/burma/ruby.yaml @@ -128,7 +128,7 @@ sections: - title: Market Position content: | - Burmese ruby in today's market: + Burmese ruby in the current market: - **Value**: Highest premiums for fine Mogok - **Pigeon blood certified**: Exceptional prices diff --git a/docs/learn/origin/cambodia.yaml b/docs/learn/origin/cambodia.yaml index 816df71..966f3f4 100644 --- a/docs/learn/origin/cambodia.yaml +++ b/docs/learn/origin/cambodia.yaml @@ -1,4 +1,4 @@ -title: Cambodia — Pailin Sapphire and Battambang Ruby +title: Cambodia – Pailin Sapphire and Battambang Ruby description: Cambodian gem deposits from Pailin (basaltic sapphire and ruby) and Battambang (marble-hosted ruby); Khmer Rouge era hiatus; distinction from Thai material. order: 10 category: origin @@ -33,17 +33,17 @@ sections: content: | Two corundum-forming environments in Cambodia: subsections: - - title: Pailin — Basaltic Province + - title: Pailin – Basaltic Province content: | - Cenozoic intraplate alkali basalt field; same Southeast Asian province as Chanthaburi-Trat (Thailand) and Ratanakiri (also Cambodia, for zircon) - Corundum transported to surface in basalt; concentrated in alluvial placers - - High-Fe, low-Cr geochemical environment — same signature as Thai basaltic material + - High-Fe, low-Cr geochemical environment – same signature as Thai basaltic material - Adjacent to Bo Rai (Thailand); material from both sides historically mixed - - title: Battambang — Marble-Hosted Ruby + - title: Battambang – Marble-Hosted Ruby content: | - - Small-scale occurrence of marble-hosted ruby — geologically analogous to + - Small-scale occurrence of marble-hosted ruby – geologically analogous to Mogok and Vietnam marble-type deposits - Low-Fe environment; strong fluorescence expected - Much smaller production volume than Pailin @@ -62,7 +62,7 @@ sections: Pailin's gem trade was historically significant as a Khmer Rouge revenue source; ethical sourcing considerations applied to Cambodian gems through the 1990s. - - title: Pailin Sapphire and Ruby — Diagnostic Features + - title: Pailin Sapphire and Ruby – Diagnostic Features content: | Characteristics of Pailin basaltic corundum: subsections: @@ -75,7 +75,7 @@ sections: - title: Chemistry and Spectroscopy content: | - - **High Fe**: Basaltic geochemical profile — >600 ppm Fe typical + - **High Fe**: Basaltic geochemical profile – >600 ppm Fe typical - **Strong 450/460/470 nm triplet**: Fe-related absorption in UV-Vis spectra, similar to Thai material - **LWUV fluorescence**: Weak; iron quenches chromium signal @@ -84,7 +84,7 @@ sections: - title: Inclusions content: | - Basalt-suite minerals: zircon (with halos), feldspar, iron oxides (ilmenite) - - Consistent with basaltic parentage — same mineral family as Thai material + - Consistent with basaltic parentage – same mineral family as Thai material - No marble-hosted inclusions (no calcite, apatite, sphene) - title: Pailin vs Thai Distinction @@ -107,7 +107,7 @@ sections: text: | The Battambang marble-hosted ruby occurrence is geologically anomalous in a province dominated by basaltic deposits. Marble-hosted ruby characteristics - (low Fe, strong fluorescence, calcite inclusions) apply — similar in principle + (low Fe, strong fluorescence, calcite inclusions) apply – similar in principle to Vietnamese marble ruby from Luc Yen, though at much smaller production scale. If marble-type inclusions are identified in a Cambodian-provenance ruby, Battambang diff --git a/docs/learn/origin/ceylon.yaml b/docs/learn/origin/ceylon.yaml index 6ce9cb8..401405f 100644 --- a/docs/learn/origin/ceylon.yaml +++ b/docs/learn/origin/ceylon.yaml @@ -60,7 +60,7 @@ sections: type: tip title: Ceylon's Signature text: | - Ceylon sapphires are known for their long, slender rutile silk— + Ceylon sapphires are known for their long, slender rutile silk – in contrast to the short silk typical of Burmese material. This long silk is one of the primary features used to identify diff --git a/docs/learn/origin/colombia-mines.yaml b/docs/learn/origin/colombia-mines.yaml index 86092d3..e57cc48 100644 --- a/docs/learn/origin/colombia-mines.yaml +++ b/docs/learn/origin/colombia-mines.yaml @@ -1,4 +1,4 @@ -title: Colombian Emerald Mines — Sub-Distinctions +title: Colombian Emerald Mines – Sub-Distinctions description: Mine-level diagnostics for Muzo (parisite + halite), Chivor (pyrite dominant), Coscuez, La Pita, and trapiche emerald; cross-reference to colombia.yaml. order: 6 category: origin @@ -29,21 +29,21 @@ sections: "black shale" or sedimentary-hosted hydrothermal model: Cretaceous black shales (Villeta Formation) host emerald-forming brines without associated igneous rocks. All three major mines share the diagnostic Colombian three-phase inclusion (liquid + - gas + halite cube) — the halite being unique to Colombian emerald worldwide. The + gas + halite cube) – the halite being unique to Colombian emerald worldwide. The mine-level distinctions below allow laboratory sub-classification. - - title: Colombian Deposit Type — The Black Shale Model + - title: Colombian Deposit Type – The Black Shale Model content: | All Colombian mines share these features: - **Host rock**: Hydrothermal veins in Cretaceous black shales/phyllites; no - nearby igneous rocks — purely sediment-hosted + nearby igneous rocks – purely sediment-hosted - **Brine**: NaCl-saturated hydrothermal fluid at ~300°C in a thrust-belt setting - - **Three-phase inclusions**: Liquid + gas + halite (NaCl) cube — the halite is + - **Three-phase inclusions**: Liquid + gas + halite (NaCl) cube – the halite is the critical discriminator from ALL other emerald origins worldwide; no other major source traps NaCl cubes in three-phase inclusions - **Chromophore**: Cr³⁺ ± V³⁺; ratio varies by mine; affects colour tone - - **Li content**: <200 ppmw — shared with Afghan and Pakistani emerald + - **Li content**: <200 ppmw – shared with Afghan and Pakistani emerald - title: Muzo Mine content: | @@ -57,15 +57,15 @@ sections: - title: Chromophore Profile content: | - - Higher **Cr** relative to V — "warmer" green, typically a pure vivid + - Higher **Cr** relative to V – "warmer" green, typically a pure vivid medium green; often the most valued pure green Colombian colour - title: Diagnostic Inclusions content: | - - **Three-phase inclusions**: Liquid + gas + halite (NaCl) cube — as all + - **Three-phase inclusions**: Liquid + gas + halite (NaCl) cube – as all Colombian - **Parisite**: Calcium rare-earth fluorocarbonate; yellow-orange hexagonal - crystals; highly diagnostic for Muzo specifically — absent in Chivor + crystals; highly diagnostic for Muzo specifically – absent in Chivor - **Albite**: White platy crystals - **Calcite rhombs** - **Pyrite**: Present but less abundant than Chivor @@ -85,13 +85,13 @@ sections: - title: Chromophore Profile content: | - - Generally **higher V relative to Cr** than Muzo — cooler, often bluish-green + - Generally **higher V relative to Cr** than Muzo – cooler, often bluish-green to teal at lower saturations; sometimes described as more "electric" blue-green - title: Diagnostic Inclusions content: | - **Three-phase inclusions**: Liquid + gas + halite (same diagnostic as all Colombian) - - **Pyrite**: Cubic metallic inclusions — far more abundant and larger at Chivor + - **Pyrite**: Cubic metallic inclusions – far more abundant and larger at Chivor than at Muzo; THIS IS THE MOST RELIABLE VISUAL MINE-LEVEL DISTINCTION - **Albite** crystals (white platy) - **Calcite** and dolomite @@ -123,7 +123,7 @@ sections: - **Trapiche emerald** was first associated with Coscuez and the adjacent Peñas Blancas area - - title: Newer Mines — La Pita, La Pava, Cunas + - title: Newer Mines – La Pita, La Pava, Cunas content: | Post-1990s mining in Boyacá Department: @@ -148,7 +148,7 @@ sections: - O'Donoghue (1971) first described this in the Journal of Gemmology: "Trapiche Emerald" - Sun, Gao, and Deng (2023) documented a rare "'Star of David' Pattern - Produced by a Trapiche Emerald from Colombia" — a geometric variant + Produced by a Trapiche Emerald from Colombia" – a geometric variant - title: Formation Mechanism content: | @@ -161,7 +161,7 @@ sections: - title: Occurrence content: | - - Primarily Coscuez and Peñas Blancas zones — NOT from Chivor + - Primarily Coscuez and Peñas Blancas zones – NOT from Chivor - Exceptional rarity: strong collector premium - Distinguished from trapiche ruby (Myanmar; different genesis) and trapiche sapphire (very rare) @@ -179,8 +179,8 @@ sections: - ["Zone", "Western", "Eastern", "Western"] - ["Chromophore", "Cr dominant", "V > Cr", "Cr dominant (like Muzo)"] - ["Colour tone", "Warm pure green", "Cooler blue-green", "Similar to Muzo"] - - ["Parisite", "YES — diagnostic", "ABSENT", "Present (like Muzo)"] - - ["Pyrite", "Minor", "Abundant — diagnostic", "Present"] + - ["Parisite", "YES – diagnostic", "ABSENT", "Present (like Muzo)"] + - ["Pyrite", "Minor", "Abundant – diagnostic", "Present"] - ["Three-phase halite", "YES (all Colombian)", "YES (all Colombian)", "YES (all Colombian)"] - ["Trapiche association", "No", "No", "YES (Coscuez + Peñas Blancas)"] diff --git a/docs/learn/origin/colombia.yaml b/docs/learn/origin/colombia.yaml index 8ef30a5..8ec190c 100644 --- a/docs/learn/origin/colombia.yaml +++ b/docs/learn/origin/colombia.yaml @@ -65,7 +65,7 @@ sections: - title: The Jardín content: | - Colombian emeralds typically have visible inclusions—the French + Colombian emeralds typically have visible inclusions – the French word "jardín" (garden) describes this internal landscape: - Inclusions more accepted than in other gems diff --git a/docs/learn/origin/east-africa/tsavorite.yaml b/docs/learn/origin/east-africa/tsavorite.yaml index cf35394..9d457e7 100644 --- a/docs/learn/origin/east-africa/tsavorite.yaml +++ b/docs/learn/origin/east-africa/tsavorite.yaml @@ -109,7 +109,7 @@ sections: - title: Market Position content: | - Tsavorite in today's gem market: + Tsavorite in the current gem market: - **Value**: Fine stones rival emerald prices - **Advantage**: No treatment required or expected diff --git a/docs/learn/origin/ethiopia.yaml b/docs/learn/origin/ethiopia.yaml index bdeafed..5a53157 100644 --- a/docs/learn/origin/ethiopia.yaml +++ b/docs/learn/origin/ethiopia.yaml @@ -1,5 +1,5 @@ -title: Ethiopia — Wollo Opal and Shakiso Emerald -description: Wollo (Welo) hydrophane opal — volcanic host, water-absorbing, distinct from Australian; Shakiso mica-schist emerald; Tigray sapphire [CITATION NEEDED]. +title: Ethiopia – Wollo Opal and Shakiso Emerald +description: Wollo (Welo) hydrophane opal – volcanic host, water-absorbing, distinct from Australian; Shakiso mica-schist emerald; Tigray sapphire [CITATION NEEDED]. order: 22 category: origin difficulty: advanced @@ -27,13 +27,13 @@ sections: - title: Introduction content: | Ethiopia has emerged as a major gem-producing country with two internationally - significant deposits: Wollo (Welo) opal — discovered 2008, characterised 2010 — + significant deposits: Wollo (Welo) opal – discovered 2008, characterised 2010 – which challenged the assumption that gem opal was primarily Australian; and Shakiso - emerald (Guji Zone, southern Ethiopia) — discovered around 2016 and immediately + emerald (Guji Zone, southern Ethiopia) – discovered around 2016 and immediately noted for fine colour. Ethiopia's gem geology reflects both Cenozoic volcanic activity (opal) and Pan-African metamorphic basement (emerald). - - title: Wollo (Welo) Opal — Discovery and Geology + - title: Wollo (Welo) Opal – Discovery and Geology content: | The Ethiopian opal revolution: subsections: @@ -42,7 +42,7 @@ sections: - Play-of-colour opal from the Wollo Province (specifically near Wegel Tena) first reported to scientific literature in 2010 - Rondeau et al. (2010) provided the foundational study: "Play-of-Color Opal - from Wegel Tena, Wollo Province, Ethiopia" — API-confirmed [VERIFIED] + from Wegel Tena, Wollo Province, Ethiopia" – API-confirmed [VERIFIED] - The study established deposit characteristics and began scientific distinction from Australian opal @@ -55,14 +55,14 @@ sections: - Geologically distinct from Australian opal: Australia is sedimentary (Cretaceous marine sediments); Ethiopia is volcanic (Tertiary rhyolite) - - title: Hydrophane — The Critical Diagnostic + - title: Hydrophane – The Critical Diagnostic content: | The defining property of Ethiopian opal: subsections: - title: What Is Hydrophane? content: | - - Ethiopian opal (especially Wollo material) is characteristically **hydrophane** - — it absorbs water, and its optical properties change measurably with hydration + - Ethiopian opal (especially Wollo material) is characteristically **hydrophane**: + it absorbs water, and its optical properties change measurably with hydration - This porous character results from the volcanic host environment and the way silica was deposited in the vugs @@ -72,14 +72,14 @@ sections: upon absorbing water it becomes more transparent and play of colour intensifies - **RI**: Increases measurably as water is absorbed (~1.37 dry → ~1.42 when wet) - **Weight**: Increases measurably when wet (3–10% weight gain in <1 hour) - - **SG**: Appears different when measured wet vs dry — hydrostatic SG measurement + - **SG**: Appears different when measured wet vs dry – hydrostatic SG measurement should NOT be performed on hydrophane opal - **Play of colour**: May change direction or intensity with hydration state - title: Reversible Colour Change with Humidity content: | - A subset of Wollo stones shows a reversible change in appearance linked to - ambient humidity — more vivid/transparent in humid conditions, more milky + ambient humidity – more vivid/transparent in humid conditions, more milky in dry conditions - This is a physical property change (water content), NOT a gem-quality optical colour change (such as the alexandrite effect) @@ -95,7 +95,7 @@ sections: blackening, sugar-acid carbonisation) can be absorbed into the opal when wet. - SMOKE TREATMENT: Exposing wet hydrophane opal to smoke deposits carbon - particles that darken the body tone, simulating black opal — partially reversible + particles that darken the body tone, simulating black opal – partially reversible - DYE IMPREGNATION: Wet opal absorbs dye solutions; detection by FTIR or UV examination - CLEANING: Ethiopian opal should NOT be cleaned ultrasonically or left in water @@ -111,7 +111,7 @@ sections: - Australian (Coober Pedy/Lightning Ridge) rows: - ["Host rock", "Tertiary rhyolitic volcanic tuff", "Cretaceous marine sediments"] - - ["Hydrophane", "Yes — typically strong", "No (non-porous in boulder opal)"] + - ["Hydrophane", "Yes – typically strong", "No (non-porous in boulder opal)"] - ["RI (dry)", "~1.37", "~1.42–1.43"] - ["SG", "~1.95–2.05 (varies with hydration)", "~2.05–2.10 (more stable)"] - ["Body tone", "White to crystal (transparent when wet)", "White (Coober Pedy); dark (Lightning Ridge black)"] @@ -136,7 +136,7 @@ sections: content: | - **Chromophores**: Cr³⁺ + V³⁺; similar Cr/V profile to Ural and Sandawana; differs from high-V Brazilian Itabira and low-Cr/high-V Zambian material - - **Fe content**: Low — contributes to good colour purity and moderate-strong + - **Fe content**: Low – contributes to good colour purity and moderate-strong red LWUV fluorescence - **Inclusions**: Phlogopite mica (more than Sandawana); tremolite needles; chlorite; two-phase fluid inclusions; apatite @@ -158,19 +158,19 @@ sections: - ["Crystal size", "Small–medium", "Very small", "Medium–large"] - ["LWUV fluorescence", "Moderate–strong red", "Very strong red", "Moderate–strong red"] - - title: Tigray Sapphire — Citation Note + - title: Tigray Sapphire – Citation Note callout: type: warning - title: CITATION NEEDED — Tigray Sapphire + title: CITATION NEEDED – Tigray Sapphire text: | Corundum (sapphire) finds in the Tigray Region (northern Ethiopia) have been reported intermittently. These appear to be high-Fe basalt-hosted sapphires - associated with Cenozoic alkalic volcanism — consistent with the high-Fe basaltic + associated with Cenozoic alkalic volcanism – consistent with the high-Fe basaltic sapphire family (Thailand, Cambodia, eastern Australia), tending toward dark, steely blue with weak fluorescence. However, no peer-reviewed gemmological characterisation paper was retrieved for - Tigray sapphire — this locality is [CITATION NEEDED] / [UNVERIFIED] per + Tigray sapphire – this locality is [CITATION NEEDED] / [UNVERIFIED] per VERIFIED.md (D-01). Specific gemmological diagnostics cannot be stated as fact; this note flags the gap for a targeted research pass. diff --git a/docs/learn/origin/india.yaml b/docs/learn/origin/india.yaml index 657fd11..25118e7 100644 --- a/docs/learn/origin/india.yaml +++ b/docs/learn/origin/india.yaml @@ -1,5 +1,5 @@ -title: India — Alexandrite, Diamond (Panna), and Garnet -description: Indian gem deposits — Andhra Pradesh alexandrite and chrysoberyl, Panna kimberlite diamond, Orissa garnet; geological context; Koh-i-Noor attribution qualified. +title: India – Alexandrite, Diamond (Panna), and Garnet +description: Indian gem deposits – Andhra Pradesh alexandrite and chrysoberyl, Panna kimberlite diamond, Orissa garnet; geological context; Koh-i-Noor attribution qualified. order: 13 category: origin difficulty: advanced @@ -42,7 +42,7 @@ sections: - ["Orissa (Odisha)", "Various districts", "Archaean basement; Precambrian metamorphic rocks", "Pyrope and almandine garnet"] - ["Tamil Nadu", "Southern India", "Garnet-bearing metamorphic basement", "Star garnet (almandine-pyrope)"] - - title: Alexandrite — Andhra Pradesh + - title: Alexandrite – Andhra Pradesh content: | Eastern Ghats chrysoberyl and alexandrite: subsections: @@ -65,14 +65,14 @@ sections: - title: Origin Determination Note content: | - Indian alexandrite is noted in the trade for its colour-change effect - but fine colour change quality — the definitive balance of green-to-red - response — is generally considered less striking than fine Ural (Russian) + but fine colour change quality – the definitive balance of green-to-red + response – is generally considered less striking than fine Ural (Russian) material - This is a generalisation based on trade consensus: the sourcing literature does not provide a peer-reviewed comparison of Indian vs Ural quality as a verified gemmological fact; individual stones vary - - title: Diamond — Panna District + - title: Diamond – Panna District content: | India's only significant primary diamond source: subsections: @@ -85,7 +85,7 @@ sections: and conglomerate deposits derived from kimberlite erosion - Active mining by NMDC (National Mineral Development Corporation) - - title: Koh-i-Noor Attribution — Critical Note + - title: Koh-i-Noor Attribution – Critical Note content: | - Various famous diamonds including the Koh-i-Noor, Regent (Pitt Diamond), and others are traditionally attributed to the alluvial workings of the @@ -96,12 +96,12 @@ sections: framework but does not attribute any specific famous diamond to Panna - For examination purposes: state that famous historic diamonds including the Koh-i-Noor are "traditionally attributed to" the Golconda/Panna - alluvial region of India — not that their Indian origin is a confirmed fact + alluvial region of India – not that their Indian origin is a confirmed fact - title: Koh-i-Noor Qualification callout: type: warning - title: VERIFIED.md Flag F-08 — Must Qualify Attribution + title: VERIFIED.md Flag F-08 – Must Qualify Attribution text: | VERIFIED.md explicitly flags (F-08): "Remove or qualify [Koh-i-Noor Panna attribution] with 'traditionally attributed'; do not present as verified @@ -111,7 +111,7 @@ sections: to the alluvial gem workings of the Golconda-Panna region of central India." Do NOT state: "The Koh-i-Noor was found at Panna" or "The Koh-i-Noor certainly - originates from Golconda" — these statements go beyond what the peer-reviewed + originates from Golconda" – these statements go beyond what the peer-reviewed record supports. - title: Diamond Origin Determination Caveat @@ -141,6 +141,6 @@ sources: - doi: "10.17491/jgsi/1996/480412" citation: "Kasipathi (1996) Chrysoberyl from Visakhapatnam and East Godavari Districts, Andhra Pradesh. Journal of the Geological Society of India." - doi: "10.17491/jgsi/2007/690306" - citation: "Rau (2007) Panna Diamond Belt, Madhya Pradesh — A Critical Review. Journal of the Geological Society of India." + citation: "Rau (2007) Panna Diamond Belt, Madhya Pradesh – A Critical Review. Journal of the Geological Society of India." - doi: "10.5741/gems.46.3.188" citation: "Shigley et al. (2010) Gem Localities of the 2000s. Gems & Gemology." diff --git a/docs/learn/origin/iran.yaml b/docs/learn/origin/iran.yaml index 6b30f90..2b598ac 100644 --- a/docs/learn/origin/iran.yaml +++ b/docs/learn/origin/iran.yaml @@ -1,5 +1,5 @@ -title: Iran — Nishapur (Neyshabur) Turquoise -description: Persian turquoise from Neyshabur, Khorasan — the global colour standard; volcanic tuff host, spider-web matrix, Cu-Al phosphate, treatment assessment. +title: Iran – Nishapur (Neyshabur) Turquoise +description: Persian turquoise from Neyshabur, Khorasan – the global colour standard; volcanic tuff host, spider-web matrix, Cu-Al phosphate, treatment assessment. order: 14 category: origin difficulty: intermediate @@ -20,7 +20,7 @@ sections: - title: Introduction content: | Persian turquoise from the Neyshabur (Nishapur) district of Khorasan-e Razavi Province - is historically the most celebrated turquoise in the world — the deposit that defined + is historically the most celebrated turquoise in the world – the deposit that defined the colour "turquoise" as a colour category for Western culture and trade. Production has continued for at least 2,000 years, making Neyshabur one of the world's longest- continuously-operating gem sources. Shirdam et al. (2021) provided a comprehensive @@ -53,7 +53,7 @@ sections: - Description - Quality rows: - - ["Robah (fox-hole)", "Even sky blue; no matrix; maximum colour saturation", "Highest — rarest"] + - ["Robah (fox-hole)", "Even sky blue; no matrix; maximum colour saturation", "Highest – rarest"] - ["Angi (vein)", "Vein material; sky blue; some matrix acceptable", "High"] - ["Arabi (Arabic)", "Good colour; moderate matrix", "Medium"] - ["Spider-web", "Matrix-patterned; mid-grade; commercially desirable", "Mid-grade commodity"] @@ -63,15 +63,15 @@ sections: type: info title: A Characteristic and Desirable Feature text: | - The "spider-web" matrix of Persian turquoise — thin veins of brown limonite - or black manganese oxide running through the turquoise in an irregular network — + The "spider-web" matrix of Persian turquoise – thin veins of brown limonite + or black manganese oxide running through the turquoise in an irregular network – is characteristic of Neyshabur material and commercially desirable in mid-grade pieces. Fine spider-web turquoise with an even blue background and well-defined matrix commands premium prices in certain markets (Native American-influenced US market and Middle Eastern markets). American Sleeping Beauty turquoise (Arizona) is notably matrix-free and more - even blue — aesthetically different from spider-web Persian material. + even blue – aesthetically different from spider-web Persian material. - title: Origin Determination content: | @@ -94,12 +94,12 @@ sections: veining; different Cu/Fe/Zn profile - Visual comparison is trade-level guidance only; analytical confirmation required - - title: Treatment — A Critical Issue + - title: Treatment – A Critical Issue callout: type: warning title: Most Neyshabur Material Is Stabilised text: | - Much of the commercial Neyshabur output is STABILISED — impregnated with wax, + Much of the commercial Neyshabur output is STABILISED – impregnated with wax, resin, or plastic to improve durability, surface finish, and colour. This is accepted trade practice but reduces value relative to untreated natural turquoise. diff --git a/docs/learn/origin/mozambique.yaml b/docs/learn/origin/mozambique.yaml index a8fe713..bc31297 100644 --- a/docs/learn/origin/mozambique.yaml +++ b/docs/learn/origin/mozambique.yaml @@ -1,5 +1,5 @@ -title: Mozambique — Montepuez Ruby and Paraíba Tourmaline -description: Montepuez ruby (Cabo Delgado) — two-type amphibolite-hosted and alluvial; Mavuco Paraíba-type Cu-bearing tourmaline; LA-ICP-MS origin discrimination. +title: Mozambique – Montepuez Ruby and Paraíba Tourmaline +description: Montepuez ruby (Cabo Delgado) – two-type amphibolite-hosted and alluvial; Mavuco Paraíba-type Cu-bearing tourmaline; LA-ICP-MS origin discrimination. order: 20 category: origin difficulty: advanced @@ -35,7 +35,7 @@ sections: Note: The east-africa/ files cover Mozambique briefly in the regional context; this file provides the Mozambique-specific depth. - - title: Montepuez Ruby — Discovery and Geology + - title: Montepuez Ruby – Discovery and Geology content: | Montepuez deposit background: subsections: @@ -53,14 +53,14 @@ sections: and chemically distinct ruby populations; this "two-type" classification is the key gemmological framework for this deposit - - title: Type A — Primary (Amphibolite-Hosted) Ruby + - title: Type A – Primary (Amphibolite-Hosted) Ruby content: | Low-Fe primary ruby from in-situ metamorphic host: subsections: - title: Geology content: | - Found in situ in amphibolite and marble-amphibolite lithologies; the host - geology is debated — some literature refers to "amphibolite-hosted," others + geology is debated – some literature refers to "amphibolite-hosted," others to serpentinite alteration of the amphibolite - Metamorphic basement representing exhumed lower crustal rocks @@ -70,10 +70,10 @@ sections: - This places Type A Mozambique ruby chemically closer to marble-hosted Mogok (Burma) than to high-Fe basaltic rubies (Thailand, Cambodia) - **Challenge**: Some Type A Mozambique rubies OVERLAP with Burmese rubies in - trace element space; Palke et al. (2019) identified this explicitly — origin + trace element space; Palke et al. (2019) identified this explicitly – origin discrimination requires multiple overlapping data sets - - title: Type B — Alluvial (Secondary) Ruby + - title: Type B – Alluvial (Secondary) Ruby content: | Higher-Fe secondary ruby from gravel pockets: @@ -91,8 +91,8 @@ sections: - title: Mineral Inclusions content: | - **Amphibole needles** (hornblende/pargasite): Elongated, greenish-black, - often in clusters — from the amphibolite metamorphic assemblage - - **Apatite crystals**: Rounded to hexagonal prisms — very diagnostic for the + often in clusters – from the amphibolite metamorphic assemblage + - **Apatite crystals**: Rounded to hexagonal prisms – very diagnostic for the Montepuez metamorphic assemblage - **Mica (phlogopite/biotite) platelets** - **Zircon with halos**: Metamict; tension fracture corona @@ -112,7 +112,7 @@ sections: text: | The combination of APATITE crystals (hexagonal prisms) and AMPHIBOLE needles (greenish-black, elongated) in a ruby is strongly associated with the Montepuez - metamorphic assemblage. This pairing reflects the amphibolite host rock — + metamorphic assemblage. This pairing reflects the amphibolite host rock – unlike the calcite + silk of Mogok, or the zircon + ilmenite of Thai basaltic ruby. - title: LA-ICP-MS Origin Determination @@ -141,7 +141,7 @@ sections: subsections: - title: Deposit content: | - - **Mavuco** deposit, Nampula Province, northern Mozambique — distinct from + - **Mavuco** deposit, Nampula Province, northern Mozambique – distinct from the Montepuez ruby district (different province) - Cu-bearing elbaite (Na(Li,Al)₃Al₆(Si₆O₁₈)(BO₃)₃(OH)₄) producing the characteristic neon blue-green Paraíba colour @@ -156,7 +156,7 @@ sections: - Mozambique: Generally higher Mn relative to Cu; Mn/Cu > ~0.3 tends to indicate African provenance (Nigeria or Mozambique) - Katsurada et al. (2019): "A combination of chemical, spectroscopic, and - gemological characteristics" required — Cu alone is insufficient + gemological characteristics" required – Cu alone is insufficient - title: Properties content: | @@ -166,7 +166,7 @@ sections: - **RI**: 1.614–1.679 (uniaxial negative); birefringence ~0.016 - **SG**: 3.01–3.06; Hardness: 7–7.5 - Market premium: Brazilian Paraíba still commands higher premiums than - Mozambican/Nigerian by 100–300% — origin certification is commercially + Mozambican/Nigerian by 100–300% – origin certification is commercially critical - title: Market Position diff --git a/docs/learn/origin/pakistan/emerald.yaml b/docs/learn/origin/pakistan/emerald.yaml index 04646ef..2ca4470 100644 --- a/docs/learn/origin/pakistan/emerald.yaml +++ b/docs/learn/origin/pakistan/emerald.yaml @@ -1,4 +1,4 @@ -title: Swat Valley Emerald — Pakistan +title: Swat Valley Emerald – Pakistan description: Ophiolite-hosted Cr-rich emerald from Mingora, Swat Valley; three-phase fluid inclusions, chromian muscovite, low Li chemistry, talc-carbonate paragenesis. order: 2 category: origin @@ -33,7 +33,7 @@ sections: content: | Swat Valley emerald genesis: subsections: - - title: Host Rock — Ophiolite Belt + - title: Host Rock – Ophiolite Belt content: | - Hosted in carbonatised ultramafic rocks (ophiolite belt) of the Indus suture zone, in the Mingora area of Swat Valley @@ -49,7 +49,7 @@ sections: interaction with the peridotite/serpentinite country rock - Arif and Moon (2007) documented chromian muscovite and tourmaline in emerald-bearing quartz veins: the muscovite shows "high Mg/Fe ratios (4–9) - and variable Ni" — geochemical evidence linking Cr directly to the ophiolitic + and variable Ni" – geochemical evidence linking Cr directly to the ophiolitic ultramafic host - title: Properties and Appearance @@ -71,7 +71,7 @@ sections: subsections: - title: Fluid Inclusions content: | - - **Three-phase fluid inclusions**: Liquid + gas + solid phases — documented + - **Three-phase fluid inclusions**: Liquid + gas + solid phases – documented for the first time in Swat emeralds by Guo et al. (2020); diagnostic for the high-salinity, high-temperature ophiolitic hydrothermal system @@ -111,7 +111,7 @@ sections: title: Talc-Carbonate (Ophiolite-Belt) Type text: | Swat Valley emerald belongs to the "talc-carbonate" or "ophiolite-hosted" deposit - type — distinct from: + type – distinct from: - SCHIST-BELT type (Zambia, Zimbabwe, Russia, Ethiopia): schist host at granite-ultramafic contact diff --git a/docs/learn/origin/pakistan/overview.yaml b/docs/learn/origin/pakistan/overview.yaml index 9d33b5e..5b06b73 100644 --- a/docs/learn/origin/pakistan/overview.yaml +++ b/docs/learn/origin/pakistan/overview.yaml @@ -1,5 +1,5 @@ -title: Pakistan — Gem Origins Overview -description: Himalayan collision zone gem deposits — Swat emerald, Hunza ruby, Katlang topaz, Skardu aquamarine; multiple geological settings. +title: Pakistan – Gem Origins Overview +description: Himalayan collision zone gem deposits – Swat emerald, Hunza ruby, Katlang topaz, Skardu aquamarine; multiple geological settings. order: 1 category: origin subcategory: pakistan @@ -44,7 +44,7 @@ sections: - ["Katlang, Mardan", "Calcite veins in recrystallised limestone", "Pink topaz"] - ["Skardu / Shigar, Baltistan", "LCT granitic pegmatites (Karakoram)", "Aquamarine, tourmaline, kunzite"] - - title: Swat Valley Emerald — Brief Overview + - title: Swat Valley Emerald – Brief Overview content: | - Hosted in carbonatised ultramafic rocks of the Indus suture zone; Cr sourced from ophiolitic chromite @@ -52,7 +52,7 @@ sections: - Low Li (<200 ppmw) shared with Colombian and Afghan emerald - See dedicated file: origin/pakistan/emerald - - title: Hunza Ruby — Brief Overview + - title: Hunza Ruby – Brief Overview content: | - Marble-hosted; low-Fe, high-Cr chemistry analogous to Mogok - Strong red LWUV fluorescence; calcite and carbonate inclusions @@ -60,9 +60,9 @@ sections: LA-ICP-MS trace element fingerprinting - See dedicated file: origin/pakistan/ruby - - title: Katlang Pink Topaz — Brief Overview + - title: Katlang Pink Topaz – Brief Overview content: | - - Colour caused by trace Cr³⁺ — rare in topaz globally + - Colour caused by trace Cr³⁺ – rare in topaz globally - Chromium colouring is the key diagnostic distinguishing from irradiation-induced pink topaz or Mn-coloured topaz - See dedicated file: origin/pakistan/topaz @@ -74,7 +74,7 @@ sections: - **Host**: Granite pegmatites intruding high-grade metamorphic and granitic rocks of the Karakoram; Baltistan and Gilgit-Baltistan produce world-class aquamarine, rubellite, green tourmaline, and kunzite - - **Quality**: Skardu-region aquamarine is among the finest globally — typically + - **Quality**: Skardu-region aquamarine is among the finest globally – typically deeply coloured, large crystals with good clarity - **Origin determination**: No distinctive chemical fingerprint for trade-level origin determination beyond provenance documentation; properties are within the diff --git a/docs/learn/origin/pakistan/ruby.yaml b/docs/learn/origin/pakistan/ruby.yaml index b15f873..9a59abb 100644 --- a/docs/learn/origin/pakistan/ruby.yaml +++ b/docs/learn/origin/pakistan/ruby.yaml @@ -1,4 +1,4 @@ -title: Hunza Ruby — Pakistan +title: Hunza Ruby – Pakistan description: Marble-hosted ruby from Hunza/Gilgit-Baltistan; low-Fe high-Cr chemistry analogous to Mogok; marble-suite inclusions; strong LWUV fluorescence. order: 3 category: origin @@ -24,7 +24,7 @@ sections: - title: Introduction content: | Ruby from the Hunza Valley (Gilgit-Baltistan) is marble-hosted corundum formed in - the Himalayan suture zone — the same broad orogenic setting that produced Mogok + the Himalayan suture zone – the same broad orogenic setting that produced Mogok (Burma), Luc Yen (Vietnam), and Kuh-i-Lal (Tajikistan) gems. Hunza ruby shares the low-iron, high-chromium chemistry of marble-hosted corundum globally and can approach Mogok quality in fine material, though production scale is small and @@ -35,7 +35,7 @@ sections: Hunza ruby formation: - **Host rock**: Corundum-bearing marble; Okrusch, Bunch, and Bank (1976) established - the petrogenesis of the Hunza marble corundum — a "corundum-bearing marble" in + the petrogenesis of the Hunza marble corundum – a "corundum-bearing marble" in the Himalayan collision zone - **Tectonic context**: Himalayan suture zone analogous to Mogok; carbonate platform rocks metamorphosed during continental collision produced marble-hosted corundum @@ -50,20 +50,20 @@ sections: content: | - Pinkish-red to red; fine quality material is comparable in colour to Mogok - Absence of iron darkening (low-Fe marble chemistry) allows Cr to dominate - the optical response — vivid, pure red + the optical response – vivid, pure red - Some material has pink modifiers; range includes pink corundum/sapphire transitional material - title: Fluorescence content: | - - **Strong red LWUV fluorescence**: High Cr, low Fe — same principle as Mogok + - **Strong red LWUV fluorescence**: High Cr, low Fe – same principle as Mogok - This is a primary distinguishing feature from Thai/Cambodian basaltic ruby where iron quenches fluorescence - title: Inclusions content: | - Calcite and carbonate minerals (marble-hosted suite) - - Primary fluid inclusions: CO₂-rich with multi-solid residues — as confirmed + - Primary fluid inclusions: CO₂-rich with multi-solid residues – as confirmed in Asian marble ruby deposits by Giuliani et al. (2015); brine compositions differ between Asian marble ruby localities - Low-Fe mineral assemblage consistent with marble protolith @@ -74,7 +74,7 @@ sections: - Both share: low Fe (<300 ppm), strong red fluorescence, marble-suite inclusions - **LA-ICP-MS required**: Trace element ratios (Ga/Mg and other patterns) can - separate Hunza from Mogok — this is a laboratory-level criterion + separate Hunza from Mogok – this is a laboratory-level criterion - **Oxygen isotopes**: Values differ subtly between marble ruby localities; isotope analysis adds discrimination power - **Specific fluid inclusion salt chemistry**: Differs between Asian marble ruby diff --git a/docs/learn/origin/pakistan/topaz.yaml b/docs/learn/origin/pakistan/topaz.yaml index d81f400..4720392 100644 --- a/docs/learn/origin/pakistan/topaz.yaml +++ b/docs/learn/origin/pakistan/topaz.yaml @@ -1,4 +1,4 @@ -title: Katlang Pink Topaz — Pakistan +title: Katlang Pink Topaz – Pakistan description: Chromium-coloured pink to champagne topaz from Katlang, Mardan district; Cr³⁺ colouring diagnostic, calcite-vein hosted, rare among topaz globally. order: 4 category: origin @@ -21,7 +21,7 @@ sections: content: | Pink topaz from the Katlang deposit in the Mardan district of Khyber Pakhtunkhwa is exceptional among topaz varieties worldwide: its pink to pinkish-orange colour - is caused by trace chromium (Cr³⁺) — an extremely rare colouring mechanism for + is caused by trace chromium (Cr³⁺) – an extremely rare colouring mechanism for topaz. Most pink topaz on the market is either irradiation-induced pink (colourless topaz irradiated and heat-treated) or Mn-coloured. Katlang material is genuinely Cr-coloured, making it diagnostically distinct and scientifically noteworthy. @@ -46,7 +46,7 @@ sections: - title: Chromium Colouring content: | - **Confirmed chromophore**: Gübelin et al. (1986) confirmed "the color is due - to trace elements — principally chromium (Cr³⁺)" + to trace elements – principally chromium (Cr³⁺)" - This Cr³⁺ substitution produces pink to pinkish-orange to champagne colour through absorption in the yellow-green region (~550 nm) @@ -84,7 +84,7 @@ sections: in the world producing topaz coloured by actual Cr³⁺ substitution into the lattice. This makes Katlang material among the most scientifically interesting topaz types - and means it will not fade under normal wearing conditions — a practical advantage + and means it will not fade under normal wearing conditions – a practical advantage over irradiation-treated pink topaz. - title: Physical Properties diff --git a/docs/learn/origin/russia/alexandrite.yaml b/docs/learn/origin/russia/alexandrite.yaml index c86ba60..7291176 100644 --- a/docs/learn/origin/russia/alexandrite.yaml +++ b/docs/learn/origin/russia/alexandrite.yaml @@ -1,5 +1,5 @@ -title: Russian Alexandrite — Tokovaya District, Ural Mountains -description: Tokovaya district alexandrite — 1830 discovery, named for Tsar Alexander II; benchmark colour change; mica-schist host; market position vs synthetic. +title: Russian Alexandrite – Tokovaya District, Ural Mountains +description: Tokovaya district alexandrite – 1830 discovery, named for Tsar Alexander II; benchmark colour change; mica-schist host; market position vs synthetic. order: 3 category: origin subcategory: russia @@ -36,9 +36,9 @@ sections: - **1830**: Russian alexandrite discovered in mica schists of the Tokovaya River district (Sanarka basin), approximately 80 km east of Yekaterinburg, Southern Urals - - Named in honour of Tsarevich Alexander (later Tsar Alexander II) — the discovery + - Named in honour of Tsarevich Alexander (later Tsar Alexander II) – the discovery reportedly occurred on the day of his coming of age - - The locality also hosts the Izumrudnye Kopi (Emerald Mines) district — the same + - The locality also hosts the Izumrudnye Kopi (Emerald Mines) district – the same mica-schist geological setting produces both alexandrite and emerald - Russian alexandrite was fashionable in late 19th century European jewellery; stones remain among the most valuable chrysoberyl specimens @@ -65,12 +65,12 @@ sections: - ["RI", "1.745–1.757 (α); birefringence 0.008–0.010"] - ["SG", "3.73"] - ["Hardness", "8.5 (Mohs)"] - - ["Pleochroism", "Trichroic — green / orange-yellow / red (strong)"] + - ["Pleochroism", "Trichroic – green / orange-yellow / red (strong)"] - ["Chelsea Colour Filter", "Pinkish-red to red (Cr³⁺ response)"] - ["Fluorescence", "Moderate red under LWUV; stronger under SWUV"] - ["Key absorption", "680 nm Cr doublet; 645 nm; 580 nm band"] - - title: Colour Change — The Russian Standard + - title: Colour Change – The Russian Standard content: | What defines Russian alexandrite quality: subsections: @@ -83,7 +83,7 @@ sections: - title: Incandescent Colour content: | - Raspberry red to purple-red; vivid and saturated in fine material - - The change should be complete — not a muddy intermediate + - The change should be complete – not a muddy intermediate - "The Russian standard": the most balanced and distinct colour change of any alexandrite source @@ -133,7 +133,7 @@ sections: and good size commands the highest prices in the alexandrite market - **Typical values**: Fine stones >1 ct: $10,000–50,000/ct depending on change quality, colour saturation, clarity, and size - - **Unheated premium**: Natural colour — no treatment issue in alexandrite; + - **Unheated premium**: Natural colour – no treatment issue in alexandrite; focus is on natural vs synthetic and origin origin - **Alternative sources**: Brazil, Sri Lanka, India, and East Africa produce alexandrite; none consistently match Ural quality; Brazilian material is the diff --git a/docs/learn/origin/russia/demantoid.yaml b/docs/learn/origin/russia/demantoid.yaml index c5d54a8..e9c7cd7 100644 --- a/docs/learn/origin/russia/demantoid.yaml +++ b/docs/learn/origin/russia/demantoid.yaml @@ -1,5 +1,5 @@ -title: Russian Demantoid Garnet — Ural Mountains -description: Ural demantoid (andradite, Cr-coloured); horsetail inclusions — byssolite terminology and Kissin 2021 mineralogical correction; LA-ICP-MS origin discrimination from Namibia and Madagascar. +title: Russian Demantoid Garnet – Ural Mountains +description: Ural demantoid (andradite, Cr-coloured); horsetail inclusions – byssolite terminology and Kissin 2021 mineralogical correction; LA-ICP-MS origin discrimination from Namibia and Madagascar. order: 2 category: origin subcategory: russia @@ -26,7 +26,7 @@ sections: variety of andradite garnet and among the most valuable of all garnets. Discovered in the 1860s from alluvial placers along the Bobrovka River (tributary of the Sysert), it is coloured by Cr³⁺ and possesses the highest dispersion (0.057 B–G interval) - of any natural garnet — exceeding diamond (0.044). The name derives from German + of any natural garnet – exceeding diamond (0.044). The name derives from German "Demant" (diamond), referring to this exceptional fire. - title: Discovery and History @@ -48,17 +48,17 @@ sections: - Property - Value rows: - - ["Species", "Andradite garnet — Ca₃Fe₂(SiO₄)₃; Cr³⁺ substituting Fe³⁺"] + - ["Species", "Andradite garnet – Ca₃Fe₂(SiO₄)₃; Cr³⁺ substituting Fe³⁺"] - ["Crystal system", "Cubic (isometric); singly refractive"] - ["RI", "1.880–1.895"] - - ["Dispersion (B–G)", "0.057 — highest of all natural garnets"] + - ["Dispersion (B–G)", "0.057 – highest of all natural garnets"] - ["SG", "~3.84"] - ["Hardness", "6.5 (Mohs)"] - ["Colour", "Yellow-green to emerald-green (Cr³⁺ dominant)"] - ["Key absorption", "685 nm Cr line; 440 nm blue-violet cutoff (iron)"] - ["Fluorescence", "Inert (iron quenches)"] - - title: The Horsetail Inclusion — Dual Terminology + - title: The Horsetail Inclusion – Dual Terminology content: | The horsetail is the most diagnostic inclusion for Ural demantoid: subsections: @@ -66,12 +66,12 @@ sections: content: | - **FGA examination terminology**: The "horsetail" inclusion consists of curved, fan-shaped bundles of fine asbestiform fibres radiating from a central chromite - crystal — described in the gemmological tradition as "byssolite" (asbestiform + crystal – described in the gemmological tradition as "byssolite" (asbestiform actinolite/amphibole variety) - This is the terminology used by major gemological laboratories in origin reports and is the description that FGA Diploma candidates must recognise - Source: Phillips & Hyrsl (1996), "Russian Demantoid, Czar of the Garnet - Family," Gems & Gemology — API-confirmed [VERIFIED] + Family," Gems & Gemology – API-confirmed [VERIFIED] - title: Mineralogical Correction (Kissin 2021) content: | @@ -80,21 +80,21 @@ sections: inclusions in the Ural demantoid were represented by hollow channels and only the outcrops, on the demantoid surface, were occasionally filled with serpentine" - The fibres are primarily HOLLOW GROWTH CHANNELS; serpentine-phase fill occurs - only at crystal surface outcrops — not byssolite or chrysotile sensu stricto + only at crystal surface outcrops – not byssolite or chrysotile sensu stricto throughout the inclusion body - - Source: Kissin et al. (2021), Minerals, doi: 10.3390/min11080825 — API-confirmed [VERIFIED] + - Source: Kissin et al. (2021), Minerals, doi: 10.3390/min11080825 – API-confirmed [VERIFIED] - - title: Horsetail Terminology — Important Clarification + - title: Horsetail Terminology – Important Clarification callout: type: warning - title: Use Both Terms — Do Not Substitute Silently + title: Use Both Terms – Do Not Substitute Silently text: | VERIFIED.md Cross-File Conflict 1 requires that BOTH descriptions be presented: FOR FGA EXAMINATIONS AND LABORATORY REPORTS: The standard description is "asbestiform fibres / byssolite radiating from a central chromite crystal" - — this reflects how major laboratories describe the inclusion and what - candidates must identify on exam papers. + (this reflects how major laboratories describe the inclusion and what + candidates must identify on exam papers). FOR SCIENTIFIC ACCURACY: Kissin et al. (2021) demonstrated the fibres are primarily hollow growth channels with serpentine fill only at surface outcrops; @@ -109,7 +109,7 @@ sections: A secondary inclusion type also confirms Ural origin: - **Diopside needles**: Krzemnicki (1999) confirmed by Raman microspectroscopy - that "diopside needles" are present as inclusions in Russian demantoid — distinct + that "diopside needles" are present as inclusions in Russian demantoid – distinct from the fibre horsetail; elongated, colourless to pale green - Combined with the horsetail, diopside needles reinforce Ural provenance - Source: doi: 10.5741/gems.35.4.192 [VERIFIED] @@ -141,7 +141,7 @@ sections: content: | Ural demantoid in the gem market: - - Commands significant premium over Namibian and Malagasy material — attributable + - Commands significant premium over Namibian and Malagasy material – attributable primarily to the horsetail inclusion and historical prestige - Fine Russian demantoid with prominent horsetail, good green colour, and >1 ct weight is among the most collectible of all garnet varieties @@ -152,9 +152,9 @@ sections: sources: - doi: "10.5741/gems.32.2.100" - citation: "Phillips & Hyrsl (1996) Russian Demantoid, Czar of the Garnet Family. Gems & Gemology. [VERIFIED — live Crossref]" + citation: "Phillips & Hyrsl (1996) Russian Demantoid, Czar of the Garnet Family. Gems & Gemology. [VERIFIED – live Crossref]" - doi: "10.3390/min11080825" - citation: "Kissin, Murzin & Karaseva (2021) 'Horsetail' Inclusions in the Ural Demantoids: Growth Formations. Minerals. [VERIFIED — live Crossref]" + citation: "Kissin, Murzin & Karaseva (2021) 'Horsetail' Inclusions in the Ural Demantoids: Growth Formations. Minerals. [VERIFIED – live Crossref]" - doi: "10.5741/gems.35.4.192" citation: "Krzemnicki (1999) Diopside needles as inclusions in demantoid garnet from Russia. Gems & Gemology. [VERIFIED]" - doi: "10.1007/s00706-019-02409-3" diff --git a/docs/learn/origin/russia/emerald.yaml b/docs/learn/origin/russia/emerald.yaml index 2b35bbd..ac0c9c9 100644 --- a/docs/learn/origin/russia/emerald.yaml +++ b/docs/learn/origin/russia/emerald.yaml @@ -1,4 +1,4 @@ -title: Ural Emerald — Malyshevsky, Russia +title: Ural Emerald – Malyshevsky, Russia description: Ural emerald from the Malyshevsky/Izumrudnye Kopi deposit; phlogopite mica inclusions diagnostic; Cr+V chromophores; mica-schist contact zone genesis. order: 4 category: origin @@ -24,7 +24,7 @@ tags: sections: - title: Introduction content: | - Ural emerald from the Malyshevsky deposit (also Izumrudnye Kopi — "Emerald Mines") + Ural emerald from the Malyshevsky deposit (also Izumrudnye Kopi – "Emerald Mines") has been mined since discovery in 1831. Located approximately 90 km northeast of Yekaterinburg in Sverdlovsk Oblast, this is the same contact zone that produces Russian alexandrite. The deposit occupies the contact between granitic pegmatites @@ -38,7 +38,7 @@ sections: - **Host rock**: Phlogopite mica schist at the contact with granitic intrusions; Laskovenkov and Zhernakov (1995) confirmed that the deposits consist of "mica schists with phlogopite" along the Tokovaya River corridor - - **Genetic model**: Same as alexandrite — pegmatite supplies Be and Al; + - **Genetic model**: Same as alexandrite – pegmatite supplies Be and Al; Cr-enriched ultramafic/schist country rock supplies Cr; the intersection of these sources at the contact zone enables beryl + Cr emerald formation - **Deposit scale**: Malysheva mine is the largest known emerald deposit in Russia; @@ -64,7 +64,7 @@ sections: content: | Russian Ural emerald inclusion suite: subsections: - - title: Primary Diagnostic — Phlogopite Mica + - title: Primary Diagnostic – Phlogopite Mica content: | - **Phlogopite mica flakes**: Brownish, tabular platelets parallel to the cleavage planes; the most characteristic and diagnostic inclusion for Ural diff --git a/docs/learn/origin/russia/overview.yaml b/docs/learn/origin/russia/overview.yaml index 810b6b3..716d34b 100644 --- a/docs/learn/origin/russia/overview.yaml +++ b/docs/learn/origin/russia/overview.yaml @@ -1,5 +1,5 @@ -title: Russia — Ural Gem Deposits Overview -description: Ural Mountains gem belt — demantoid garnet, alexandrite, emerald; Yakutia diamond; serpentinite and mica-schist geological settings. +title: Russia – Ural Gem Deposits Overview +description: Ural Mountains gem belt – demantoid garnet, alexandrite, emerald; Yakutia diamond; serpentinite and mica-schist geological settings. order: 1 category: origin subcategory: russia @@ -31,7 +31,7 @@ sections: Late Palaeozoic (350–290 Ma) suturing of the Russian and Siberian plates. Russia also hosts the world's largest diamond production by volume in Yakutia - (Sakha Republic, eastern Siberia) — geographically and geologically distinct + (Sakha Republic, eastern Siberia) – geographically and geologically distinct from the Ural gem belt. - title: Geological Settings @@ -45,22 +45,22 @@ sections: - ["Mica-schist / phlogopite contact zones", "Tokovaya River district", "Alexandrite, emerald"] - ["Kimberlite pipes", "Yakutia / Sakha Republic (eastern Siberia)", "Diamond (Russian diamond)"] - - title: Demantoid Garnet — Brief Overview + - title: Demantoid Garnet – Brief Overview content: | - Discovered 1860s; Bobrovka River and Sysert area, Sverdlovsk Oblast - Andradite garnet (Ca₃Fe₂(SiO₄)₃), Cr³⁺-coloured; highest dispersion of - any natural garnet (0.057 — exceeds diamond 0.044) + any natural garnet (0.057 – exceeds diamond 0.044) - "Horsetail" inclusion is the single most diagnostic Ural feature - See dedicated file: origin/russia/demantoid - - title: Alexandrite — Brief Overview + - title: Alexandrite – Brief Overview content: | - Discovered 1830; Tokovaya River district, ~80 km east of Yekaterinburg - Named for Tsarevich Alexander (later Tsar Alexander II) - Russian alexandrite = global benchmark for colour-change quality - See dedicated file: origin/russia/alexandrite - - title: Ural Emerald — Brief Overview + - title: Ural Emerald – Brief Overview content: | - Izumrudnye Kopi (Emerald Mines) + Malyshevsky deposit; ~90 km NE of Yekaterinburg - Phlogopite mica inclusions are most diagnostic feature for Ural provenance @@ -75,7 +75,7 @@ sections: underground mining continues - **Udachnaya, Aikhal, Jubilee pipes** (Nyurba field): Major modern producers - Russian Yakutian diamonds show the standard kimberlitic inclusion suite - (olivine/forsterite, pyrope garnet, chrome diopside, graphite) — no unique + (olivine/forsterite, pyrope garnet, chrome diopside, graphite) – no unique macro-diagnostic features that distinguish them from other kimberlitic origins at the gemmological bench level - Separation from HPHT or CVD synthetic diamond uses standard spectroscopic diff --git a/docs/learn/origin/tajikistan.yaml b/docs/learn/origin/tajikistan.yaml index 72796e6..d658dd4 100644 --- a/docs/learn/origin/tajikistan.yaml +++ b/docs/learn/origin/tajikistan.yaml @@ -1,5 +1,5 @@ -title: Tajikistan — Kuh-i-Lal Spinel (Balas Ruby) -description: Kuh-i-Lal Gorno-Badakhshan red and pink spinel — historic "Balas ruby" of the Persian courts; Cr-coloured marble-hosted; trace element distinction from Mogok and Luc Yen. +title: Tajikistan – Kuh-i-Lal Spinel (Balas Ruby) +description: Kuh-i-Lal Gorno-Badakhshan red and pink spinel – historic "Balas ruby" of the Persian courts; Cr-coloured marble-hosted; trace element distinction from Mogok and Luc Yen. order: 12 category: origin difficulty: advanced @@ -25,8 +25,8 @@ sections: content: | The Kuh-i-Lal deposit in the Gorno-Badakhshan Autonomous Region of Tajikistan is the world's most historically celebrated red spinel locality. Known for centuries - as the source of "Balas ruby" — a Persian trade name for red spinel before spinel - was distinguished from ruby as a separate species — it supplied the gem courts of + as the source of "Balas ruby" – a Persian trade name for red spinel before spinel + was distinguished from ruby as a separate species – it supplied the gem courts of the Islamic world, Persia, and Mughal India. The Black Prince's Ruby (set in the Imperial State Crown of the United Kingdom) and the Timur Ruby are both Kuh-i-Lal red spinels. The deposit lies in the same Himalayan orogenic belt as Mogok (Burma) @@ -39,7 +39,7 @@ sections: - title: Himalayan Belt Affiliation content: | - Located in Badakhshan, geographically adjacent to Afghanistan's Sar-e-Sang - lapis mines — both deposits sit in the same Badakhshan province + lapis mines – both deposits sit in the same Badakhshan province - Part of the marble-hosted gem spinel belt extending from Mogok (Myanmar) through Luc Yen (Vietnam) to Kuh-i-Lal; Malsy and Klemm (2010) stated "Gem spinel deposits in Myanmar, Vietnam and Tajikistan have their formation @@ -75,7 +75,7 @@ sections: - title: Fluorescence content: | - - Strong red fluorescence under LWUV — Cr³⁺ dominant, relatively low Fe + - Strong red fluorescence under LWUV – Cr³⁺ dominant, relatively low Fe - Similar in principle to Mogok ruby and Luc Yen spinel fluorescence - title: Trace Element Origin Determination @@ -123,7 +123,7 @@ sections: text: | Before the 18th century, red spinel and ruby were not distinguished as separate gem species. The name "Balas ruby" (from Balascia, the medieval name for Badakhshan) - referred to red stones from the Kuh-i-Lal region — most of which are spinel. + referred to red stones from the Kuh-i-Lal region – most of which are spinel. Famous "rubies" in royal collections worldwide were later identified as Kuh-i-Lal spinel: diff --git a/docs/learn/origin/thailand/overview.yaml b/docs/learn/origin/thailand/overview.yaml index b43072c..e404e1d 100644 --- a/docs/learn/origin/thailand/overview.yaml +++ b/docs/learn/origin/thailand/overview.yaml @@ -1,4 +1,4 @@ -title: Thailand — Gem Origins Overview +title: Thailand – Gem Origins Overview description: Southeast Asian gem province centred on Chanthaburi, Trat, Kanchanaburi, Bo Phloi, and Bo Rai; world leader in corundum heat treatment and trading. order: 1 category: origin @@ -43,15 +43,15 @@ sections: - **Concentration**: Gems accumulate in alluvial and eluvial placers derived from weathered basalt - **Chemistry**: Basaltic environment imposes high-Fe, low-Cr signature on - corundum — the defining geochemical contrast with marble-hosted Mogok ruby + corundum – the defining geochemical contrast with marble-hosted Mogok ruby - title: Tectonic Context content: | - Post-subduction intraplate extension of the Indochina microplate - Multi-stage sapphire formation at Bo Phloi reflects separate pulses of basaltic magmatism - - Same Southeast Asian alkaline basalt province as Cambodian Pailin field - — deposits merge across the border + - Same Southeast Asian alkaline basalt province as Cambodian Pailin field; + deposits merge across the border - title: Mining Areas table: diff --git a/docs/learn/origin/thailand/ruby.yaml b/docs/learn/origin/thailand/ruby.yaml index 92d7ebf..b3cfb74 100644 --- a/docs/learn/origin/thailand/ruby.yaml +++ b/docs/learn/origin/thailand/ruby.yaml @@ -1,4 +1,4 @@ -title: Thai Ruby — Chanthaburi-Trat and Bo Rai Types +title: Thai Ruby – Chanthaburi-Trat and Bo Rai Types description: Basaltic-hosted Siam ruby from Chanthaburi-Trat and Bo Rai; diagnostic high-Fe chemistry, 451/460/470 nm iron triplet, weak fluorescence, alluvial habit. order: 2 category: origin @@ -41,12 +41,12 @@ sections: blue-green region and shifts the colour toward brownish-red - **Saturation**: High in fine material but rarely achieves the vivid "pigeon blood" quality of Mogok ruby - - **Fluorescence response**: Colour appears dull or dead under UV — iron + - **Fluorescence response**: Colour appears dull or dead under UV – iron strongly quenches chromium fluorescence - title: Transparency and Cut content: | - - Typically water-worn, rounded alluvial pebbles — evidence of secondary deposit + - Typically water-worn, rounded alluvial pebbles – evidence of secondary deposit - Variable clarity; extensive rutile silk common - Most commercial material is heat-treated to improve colour and clarity @@ -96,7 +96,7 @@ sections: subsections: - title: Chemical Criteria (LA-ICP-MS) content: | - - **Fe content**: High (>600 ppm; often >1,000 ppm) — primary criterion + - **Fe content**: High (>600 ppm; often >1,000 ppm) – primary criterion - **Fe/Cr ratio**: High relative to marble-hosted ruby - **Ga/Mg**: Basaltic sapphire signature; specific ratio differs from marble-hosted - **Low Cr relative to Fe**: Weak chromium signal suppressed by high iron @@ -104,8 +104,8 @@ sections: - title: Optical / Spectroscopic Criteria content: | - Very strong 451/460/470 nm iron absorption triplet in UV-Vis - - LWUV fluorescence: Weak to inert (iron quenches chromium fluorescence) - — major contrast with marble-hosted ruby + - LWUV fluorescence: Weak to inert (iron quenches chromium fluorescence), + a major contrast with marble-hosted ruby - Chromium doublet at 692/694 nm present but may be accompanied by strong broad iron absorption - Chelsea filter: May appear weakly red (Cr present) but less vividly than diff --git a/docs/learn/origin/thailand/sapphire.yaml b/docs/learn/origin/thailand/sapphire.yaml index fa2020a..4e08dc3 100644 --- a/docs/learn/origin/thailand/sapphire.yaml +++ b/docs/learn/origin/thailand/sapphire.yaml @@ -1,4 +1,4 @@ -title: Thai Sapphire — Bo Phloi and Kanchanaburi Types +title: Thai Sapphire – Bo Phloi and Kanchanaburi Types description: Basaltic high-Fe blue sapphire from Bo Phloi and Kanchanaburi; strong 450/460/470 nm iron triplet, common heat treatment, basalt-suite inclusions. order: 3 category: origin @@ -39,7 +39,7 @@ sections: - **Black star**: Star sapphire with opaque body - **Golden star**: Asterism in yellowish material - The very dark tone of Thai blue sapphires — often darker than Kashmir or Ceylon — + The very dark tone of Thai blue sapphires – often darker than Kashmir or Ceylon – results from the combined effect of high-Fe absorption across the visible spectrum. - title: Diagnostic Inclusions @@ -56,12 +56,12 @@ sections: - title: Contact-Metamorphic Suite content: | - Hercynitic spinel (dark, opaque) - - Zircon crystals — common; often with radiation damage halos + - Zircon crystals – common; often with radiation damage halos - Manganiferous ilmenite (black opaque) - Silica-rich enstatite (pyroxene) - Almandine-pyrope garnet - Staurolite - - Calcite (occasional — from xenolith material) + - Calcite (occasional – from xenolith material) - Monazite (rare, distinctive) - title: Inclusion Significance diff --git a/docs/learn/origin/thailand/zircon.yaml b/docs/learn/origin/thailand/zircon.yaml index 10eee15..25ce72c 100644 --- a/docs/learn/origin/thailand/zircon.yaml +++ b/docs/learn/origin/thailand/zircon.yaml @@ -1,4 +1,4 @@ -title: Thai Blue Zircon — Heat-Treatment Hub +title: Thai Blue Zircon – Heat-Treatment Hub description: Thailand as the global centre for heat-treating Cambodian and Vietnamese zircon rough into blue zircon; origin, treatment process, and identification. order: 4 category: origin @@ -19,7 +19,7 @@ tags: sections: - title: Introduction content: | - Thailand — primarily Chanthaburi and Bangkok — is the world's dominant centre + Thailand – primarily Chanthaburi and Bangkok – is the world's dominant centre for the production of faceted blue zircon. The majority of blue zircon on the market has not been mined in Thailand but has been heat-treated there: brownish to colourless zircon rough from Cambodia and Vietnam is imported and heated to @@ -52,7 +52,7 @@ sections: - title: Colour Results content: | - - **Blue to blue-green**: The primary commercial goal — the classic "blue zircon" + - **Blue to blue-green**: The primary commercial goal – the classic "blue zircon" - **Colourless**: Some rough heats to colourless (diamond simulant use) - **Golden to orange**: Produced by heating in reducing conditions (less common) - **Colour stability**: Blue zircon colour can fade slightly in strong light over @@ -94,7 +94,7 @@ sections: - Treatment is accepted and standard; laboratories report it as "Evidence of heat treatment" on origin reports - Chemical origin determination of zircon (Cambodia vs Vietnam vs elsewhere) - uses U-Pb age dating and trace element profiles — not routine in the gem trade + uses U-Pb age dating and trace element profiles – not routine in the gem trade - "Thai blue zircon" as a label refers to the treatment location, not the mining origin of the rough diff --git a/docs/learn/origin/usa/montana-sapphire.yaml b/docs/learn/origin/usa/montana-sapphire.yaml index 3319040..da24c0f 100644 --- a/docs/learn/origin/usa/montana-sapphire.yaml +++ b/docs/learn/origin/usa/montana-sapphire.yaml @@ -1,4 +1,4 @@ -title: Montana Sapphire — Yogo Gulch, Rock Creek, Missouri River +title: Montana Sapphire – Yogo Gulch, Rock Creek, Missouri River description: Yogo Gulch steely-blue lamprophyre sapphire (no heat needed), Rock Creek and Missouri River alluvial pastels; distinct Fe/Ti/Mg trace element chemistry; US commercial significance. order: 2 category: origin @@ -26,11 +26,11 @@ sections: content: | Montana is the principal sapphire state in the USA, with three distinct deposit types producing gemstones of different character. Yogo Gulch, discovered in 1895, - produces the most distinctive sapphires — a steely to cornflower blue that rarely + produces the most distinctive sapphires – a steely to cornflower blue that rarely requires heat treatment. Rock Creek and the Missouri River deposits supply a broader colour range, most of which is heat-treated for commercial blue. - - title: Yogo Gulch — The Defining Montana Deposit + - title: Yogo Gulch – The Defining Montana Deposit content: | Yogo Gulch sapphire characteristics: subsections: @@ -41,13 +41,13 @@ sections: - Palke, Renfro, and Berg (2016) investigated the lamprophyre host and melt inclusions: Yogo is geologically related to subduction-related alkalic magmatism - Palke et al. (2018) documented a geochemical link: "A common origin for - Thai/Cambodian rubies and blue and violet sapphires from Yogo Gulch, Montana" - — both derive from subduction-related alkalic magmas, though Yogo's chemistry + Thai/Cambodian rubies and blue and violet sapphires from Yogo Gulch, Montana"; + both derive from subduction-related alkalic magmas, though Yogo's chemistry differs in detail - title: Colour content: | - - **Steely blue to violet-blue**: Uniform, even saturation throughout — rarely + - **Steely blue to violet-blue**: Uniform, even saturation throughout – rarely shows colour zoning - Compared to Kashmir: steelier, less "velvety"; more uniform but less silky - No colour change; no parti-colour @@ -57,26 +57,26 @@ sections: - title: Size and Heat Treatment content: | - Almost never exceeds 2 ct faceted; the vast majority are ≤0.5 ct - - Flat, tabular crystal habit gives very low cutting yield — explains rarity + - Flat, tabular crystal habit gives very low cutting yield – explains rarity of larger stones - **No heat treatment needed**: Low Fe content means little silk or rutile - to dissolve; Yogo stones appear similar heated or unheated — historically + to dissolve; Yogo stones appear similar heated or unheated – historically treated as unnecessary and rarely performed - This "naturally heat-treatment-free" quality is unusual for a sapphire with any basaltic/lamprophyre association - title: Trace Element Chemistry content: | - - **Relatively low Fe** compared to Thai/Cambodian basaltic sapphire — + - **Relatively low Fe** compared to Thai/Cambodian basaltic sapphire – explains the clear blue rather than dark greenish-blue inky tone - - **Low Cr** — no Cr lines; pure Fe-Ti coloration + - **Low Cr** – no Cr lines; pure Fe-Ti coloration - Krebs et al. (2020) demonstrated that Montana sapphires can be separated from Asian basaltic sapphires using Ga/Mg, Fe/Ti, and Cr/Ga ratios; Yogo shows distinctively low Fe and low Cr/Ga - title: Inclusions content: | - - Few inclusions; characteristic lack of silk (rutile needles) — unusual + - Few inclusions; characteristic lack of silk (rutile needles) – unusual for a basalt/lamprophyre associated sapphire - Irregular liquid-filled cavities; two-phase inclusions - No marble-suite inclusions diff --git a/docs/learn/origin/usa/overview.yaml b/docs/learn/origin/usa/overview.yaml index ec99caf..caf527c 100644 --- a/docs/learn/origin/usa/overview.yaml +++ b/docs/learn/origin/usa/overview.yaml @@ -1,5 +1,5 @@ -title: USA — Gem Origins Overview -description: US gem deposits — Montana sapphire, Utah red beryl, Arizona peridot, California and Maine tourmaline; geologically diverse patchwork provinces. +title: USA – Gem Origins Overview +description: US gem deposits – Montana sapphire, Utah red beryl, Arizona peridot, California and Maine tourmaline; geologically diverse patchwork provinces. order: 1 category: origin subcategory: usa @@ -45,20 +45,20 @@ sections: - ["California", "Pala District, San Diego County", "Cretaceous LCT pegmatite", "Elbaite tourmaline"] - ["Maine", "Oxford County pegmatites", "LCT granite pegmatite", "Elbaite tourmaline (blue/green)"] - - title: Montana Sapphire — Brief Overview + - title: Montana Sapphire – Brief Overview content: | - Three deposit types: Yogo Gulch (lamprophyre), Rock Creek (alluvial), Missouri River - Yogo: steely blue, rarely >2 ct, no heat treatment needed; low Fe; lamprophyre host - Rock Creek / Missouri River: pastel multicolour; mostly heat-treated for commercial blue - See dedicated file: origin/usa/montana-sapphire - - title: Utah Red Beryl — Brief Overview + - title: Utah Red Beryl – Brief Overview content: | - - Wah Wah Mountains, Beaver County — the world's only commercial red beryl source + - Wah Wah Mountains, Beaver County – the world's only commercial red beryl source - Hosted in Eocene topaz rhyolite; Mn³⁺ chromophore; typically <0.5 ct - See dedicated file: origin/usa/utah-red-beryl - - title: Arizona Peridot — San Carlos + - title: Arizona Peridot – San Carlos content: | San Carlos Apache Reservation (Gila County) produces an estimated 80–95% of commercial peridot by volume: @@ -85,7 +85,7 @@ sections: - Discrimination between California and Maine deposits, and between US and other tourmaline origins, is a laboratory-level task requiring trace element chemistry - - title: US Tourmaline and Arkansas Diamond — Notes + - title: US Tourmaline and Arkansas Diamond – Notes callout: type: info title: CITATION NEEDED Items @@ -95,12 +95,12 @@ sections: was retrieved: 1. US TOURMALINE sub-deposit distinction (Maine vs California): No specific - inter-deposit discrimination paper retrieved — [CITATION NEEDED]. + inter-deposit discrimination paper retrieved – [CITATION NEEDED]. Include as brief item only without diagnostic claims. 2. ARKANSAS DIAMOND (Crater of Diamonds, Murfreesboro): Lamproite-hosted; educational "finders-keepers" site; negligible commercial production. - No peer-reviewed gemological characterisation retrieved — [CITATION NEEDED]. + No peer-reviewed gemological characterisation retrieved – [CITATION NEEDED]. Mention only as educational context; do not assign gemmological diagnostics. sources: diff --git a/docs/learn/origin/usa/utah-red-beryl.yaml b/docs/learn/origin/usa/utah-red-beryl.yaml index 5eee682..cd0ac33 100644 --- a/docs/learn/origin/usa/utah-red-beryl.yaml +++ b/docs/learn/origin/usa/utah-red-beryl.yaml @@ -1,5 +1,5 @@ -title: Utah Red Beryl — Wah Wah Mountains -description: World's only commercial red beryl source — Mn³⁺-coloured beryl in Eocene topaz rhyolite, Wah Wah Mountains, Utah; properties, inclusions, market rarity. +title: Utah Red Beryl – Wah Wah Mountains +description: World's only commercial red beryl source – Mn³⁺-coloured beryl in Eocene topaz rhyolite, Wah Wah Mountains, Utah; properties, inclusions, market rarity. order: 3 category: origin subcategory: usa @@ -21,18 +21,18 @@ tags: sections: - title: Introduction content: | - Red beryl — commercially known as "bixbite" (though this trade name overlaps with - the manganese oxide mineral bixbyite, causing confusion) — is arguably the rarest + Red beryl – commercially known as "bixbite" (though this trade name overlaps with + the manganese oxide mineral bixbyite, causing confusion) – is arguably the rarest gem-quality beryl variety. Commercial production occurs at essentially one location in the world: the Wah Wah Mountains of Beaver County, Utah. Shigley and Foord (1984) provided the definitive characterisation: stones occupy "vugs and fractures in a - topaz rhyolite" — a uniquely volcanic gem beryl occurrence. + topaz rhyolite" – a uniquely volcanic gem beryl occurrence. - title: Geological Setting content: | Wah Wah Mountains red beryl geology: - - **Host rock**: Topaz rhyolite — a silica-rich, F-bearing volcanic flow — of + - **Host rock**: Topaz rhyolite – a silica-rich, F-bearing volcanic flow – of Eocene age (~20–19 Ma), formed during Basin and Range extensional tectonics - **Formation mechanism**: Beryl crystallises from an F-rich hydrothermal/vapour phase generated during cooling of the rhyolitic magma; this vapour phase @@ -51,7 +51,7 @@ sections: consistent but saturation varies - **Chromophore**: Mn³⁺ substituting Al³⁺ in the beryl structure - Mn³⁺ absorption band in the ~490–560 nm region gives the red colour by - absorbing blue-green light — the complement of red + absorbing blue-green light – the complement of red - This is fundamentally different from the Cr³⁺ colouring of ruby or emerald - title: Properties @@ -75,7 +75,7 @@ sections: - **Two-phase inclusions**: Liquid + gas - **Growth tubes**: Parallel to the c-axis - - **Topaz crystals**: From the same rhyolitic host — geologically associate + - **Topaz crystals**: From the same rhyolitic host – geologically associate - **Bixbyite crystals**: Iron-manganese oxide; small black cuboids - **Hematite**: Iron oxide - **Needle-like inclusions**: Occasionally present @@ -88,7 +88,7 @@ sections: content: | - Red spinel is isotropic (cubic); red beryl is uniaxial negative (hexagonal) - On polariscope: spinel SR, red beryl DR - - SG differs: spinel ~3.60; red beryl ~2.67 — major difference + - SG differs: spinel ~3.60; red beryl ~2.67 – major difference - RI differs: spinel 1.712–1.736; red beryl 1.564–1.590 - title: From Rubellite (Red Tourmaline) @@ -102,7 +102,7 @@ sections: - title: From Red Glass content: | - - Glass is isotropic; red beryl is doubly refractive — polariscope separation + - Glass is isotropic; red beryl is doubly refractive – polariscope separation - SG of glass varies but usually 2.3–4.5; red beryl SG is characteristic - Chelsea filter and spectrum may help confirm beryl species diff --git a/docs/learn/origin/vietnam.yaml b/docs/learn/origin/vietnam.yaml index bb433f5..84cea60 100644 --- a/docs/learn/origin/vietnam.yaml +++ b/docs/learn/origin/vietnam.yaml @@ -1,4 +1,4 @@ -title: Vietnam — Luc Yen Ruby and Cobalt-Blue Spinel +title: Vietnam – Luc Yen Ruby and Cobalt-Blue Spinel description: Marble-hosted ruby and spinel from Luc Yen (Yen Bai) and Quy Chau; low-Fe high-Cr chemistry, cobalt-blue spinel, distinction from Burmese material. order: 11 category: origin @@ -30,7 +30,7 @@ sections: (Nghe An Province) produce ruby and spinel in a geological setting analogous to Mogok, Burma: Himalayan-related metamorphism of carbonate-platform sequences yielded gem-quality corundum and spinel in marble. Vietnam also hosts the world's leading - source of cobalt-blue spinel — a unique and highly prized material. + source of cobalt-blue spinel – a unique and highly prized material. - title: Geological Context content: | @@ -52,7 +52,7 @@ sections: - Marble-hosted ruby; historically the entry point for Vietnamese rubies into the international market - - title: Ruby — Luc Yen and Quy Chau Types + - title: Ruby – Luc Yen and Quy Chau Types content: | Characteristics of Vietnamese marble-hosted ruby: subsections: @@ -61,16 +61,16 @@ sections: - Vivid pinkish-red to red; can approach Mogok quality - Often lighter and more saturated than Thai basaltic ruby; some with slight pinkish or purplish modifiers - - Typically lower clarity than Mogok material — much production is cabochon + - Typically lower clarity than Mogok material – much production is cabochon or star quality - title: Diagnostic Inclusions content: | - **Calcite rhombs**: Marble-hosted environment; characteristic of all marble-type corundum globally - - **Pyrrhotite**: Iron sulfide crystals — highly diagnostic for Luc Yen + - **Pyrrhotite**: Iron sulfide crystals – highly diagnostic for Luc Yen - **Nordstrandite**: Rare aluminium hydroxide mineral; documented in Luc Yen - ruby by Kane et al. (1991) — very unusual in corundum globally + ruby by Kane et al. (1991) – very unusual in corundum globally - **Bluish colour zones and angular growth features**: Characteristic of Vietnamese marble ruby - **Fluid inclusions**: CO₂-rich primary inclusions with multi-solid residues; @@ -78,7 +78,7 @@ sections: - title: Spectroscopy and Fluorescence content: | - - **LWUV fluorescence**: Strong red — critical contrast with Thai/Cambodian + - **LWUV fluorescence**: Strong red – critical contrast with Thai/Cambodian basaltic rubies where iron quenches fluorescence - **Low Fe**: Marble-hosted chemistry; typically <300 ppm Fe by LA-ICP-MS - **High Cr**: Dominant chromophore; similar principle to Mogok @@ -103,12 +103,12 @@ sections: - ["Fe content", "Low (<300 ppm)", "Low (<300 ppm)"] - ["LWUV fluorescence", "Strong red", "Strong red"] - ["Key inclusions", "Pyrrhotite, nordstrandite, calcite", "Calcite, apatite, sphene, silk"] - - ["Ga/Mg ratio", "Relatively higher Ga", "Lower Ga — lab criterion"] + - ["Ga/Mg ratio", "Relatively higher Ga", "Lower Ga – lab criterion"] - ["Colour zones", "Bluish zones, angular features", "Irregular; treacle swirls"] - ["Fluorescence nuance", "Strong red (similar to Mogok)", "Strong red (benchmark)"] - ["Lab separation", "LA-ICP-MS Ga/Mg + inclusions", "Reference standard"] - - title: Spinel — Cobalt-Blue Luc Yen Type + - title: Spinel – Cobalt-Blue Luc Yen Type content: | Vietnam's most celebrated and distinctive gem material: subsections: @@ -117,7 +117,7 @@ sections: - Luc Yen is the world's leading source of vivid blue spinel coloured by Co²⁺ - Co²⁺ substitution is rare in spinel globally; most blue spinel is Fe-coloured - Chauviré et al. (2015) established that the blue "is due to cobalt (Co²⁺), - with some iron contribution" — a marble metamorphic genesis + with some iron contribution" – a marble metamorphic genesis - UV-Vis spectroscopy: Cobalt produces three characteristic absorption bands; the Co²⁺ spectrum is distinctive from Fe-coloured blue spinel diff --git a/docs/learn/origin/zimbabwe.yaml b/docs/learn/origin/zimbabwe.yaml index 226eb5e..d8efc77 100644 --- a/docs/learn/origin/zimbabwe.yaml +++ b/docs/learn/origin/zimbabwe.yaml @@ -1,5 +1,5 @@ -title: Zimbabwe — Sandawana Emerald and Marange Diamond -description: Sandawana (Belingwe) emerald — vivid Cr-rich, tremolite inclusions, very small; Marange alluvial diamond; Murehwa chrysoberyl [CITATION NEEDED]. +title: Zimbabwe – Sandawana Emerald and Marange Diamond +description: Sandawana (Belingwe) emerald – vivid Cr-rich, tremolite inclusions, very small; Marange alluvial diamond; Murehwa chrysoberyl [CITATION NEEDED]. order: 21 category: origin difficulty: advanced @@ -24,13 +24,13 @@ sections: - title: Introduction content: | Zimbabwe hosts two internationally significant gem deposits: Sandawana emerald from - the Belingwe (Mberengwa) district — known for its exceptionally saturated small - crystals — and the Marange alluvial diamond field (Manicaland Province), which + the Belingwe (Mberengwa) district – known for its exceptionally saturated small + crystals – and the Marange alluvial diamond field (Manicaland Province), which became controversial due to human rights concerns. Sandawana is the more important gemmological reference deposit; Marange is commercially significant but gemmologically less characterised in peer-reviewed literature. - - title: Sandawana Emerald — Overview + - title: Sandawana Emerald – Overview content: | The defining characteristics of Sandawana: subsections: @@ -58,23 +58,23 @@ sections: - **Colour**: Vivid, pure grass-green to emerald-green; colour saturation among the highest of any natural emerald; often described as "vivid green" without - blue modifiers — the emerald equivalent of "pigeon blood" quality - - **Chromophores**: Cr³⁺ dominant; minimal V; very low Fe — the low Fe is the + blue modifiers – the emerald equivalent of "pigeon blood" quality + - **Chromophores**: Cr³⁺ dominant; minimal V; very low Fe – the low Fe is the key to the exceptional colour purity and very strong red fluorescence - - **UV Fluorescence (LWUV)**: Very strong red — one of the highest Cr-driven + - **UV Fluorescence (LWUV)**: Very strong red – one of the highest Cr-driven fluorescence intensities among natural emeralds; significantly stronger than Zambian (higher Fe) or Colombian material - **Chelsea Colour Filter**: Strong red (Cr dominant) - **Size constraint**: Almost invariably <0.5 ct commercial material; 0.1–0.3 ct typical; stones >1 ct are exceptional and command premium prices - - title: Diagnostic Inclusions — Tremolite Needles + - title: Diagnostic Inclusions – Tremolite Needles callout: type: tip title: Tremolite as the Primary Diagnostic text: | TREMOLITE NEEDLES (calcium magnesium amphibole) are the primary diagnostic - inclusion for Sandawana origin — as confirmed by Zwaan and Burke (1998) using + inclusion for Sandawana origin – as confirmed by Zwaan and Burke (1998) using Raman microspectroscopy. These are straight, slender, colourless to pale needles, often in parallel groups. @@ -88,7 +88,7 @@ sections: content: | Complete inclusion suite: - - Talc (soft, platy) — from the talc-schist host + - Talc (soft, platy) – from the talc-schist host - Chlorite flakes - Dolomite and calcite rhombs - Two-phase fluid inclusions (liquid + gas) @@ -102,7 +102,7 @@ sections: and Brazilian material; LA-ICP-MS is confirmatory 2. **Tremolite needle inclusions**: Primary visual diagnostic (Zwaan & Burke 1998) 3. **Very small crystal size**: <0.5 ct in virtually all commercial material - 4. **Strong red LWUV fluorescence**: Very strong — much stronger than most other + 4. **Strong red LWUV fluorescence**: Very strong – much stronger than most other emerald origins at equivalent saturation - title: Sandawana vs Key Emerald Origins @@ -142,15 +142,15 @@ sections: suite unique to Marange has been documented in peer-reviewed gemmological literature retrieved from the research database - - title: Murehwa Chrysoberyl — Citation Note + - title: Murehwa Chrysoberyl – Citation Note callout: type: warning - title: CITATION NEEDED — Murehwa Chrysoberyl + title: CITATION NEEDED – Murehwa Chrysoberyl text: | The Murehwa district (Mashonaland East Province) is noted as hosting LCT pegmatites carrying chrysoberyl, occasionally of alexandrite quality. However, no peer-reviewed gemmological characterisation paper for Murehwa chrysoberyl was retrieved from - the research database — this locality is [UNVERIFIED] per VERIFIED.md (D-05). + the research database – this locality is [UNVERIFIED] per VERIFIED.md (D-05). It is noted here for completeness; specific gemmological diagnostics cannot be stated without a sourced paper. Colour change is reportedly modest compared diff --git a/docs/learn/phenomena/alexandrite-effect.yaml b/docs/learn/phenomena/alexandrite-effect.yaml index 644055d..d6c3075 100644 --- a/docs/learn/phenomena/alexandrite-effect.yaml +++ b/docs/learn/phenomena/alexandrite-effect.yaml @@ -1,5 +1,5 @@ -title: Alexandrite Effect — Physical Mechanism -description: Deep dive into the alexandrite effect — Cr³⁺ in trigonal crystal field, the dual transmission window, photopic peak balance, named species including garnets, sapphire, and synthetic spinel, and how to test colour change under standardised illuminants. +title: Alexandrite Effect – Physical Mechanism +description: Deep dive into the alexandrite effect – Cr³⁺ in trigonal crystal field, the dual transmission window, photopic peak balance, named species including garnets, sapphire, and synthetic spinel, and how to test colour change under standardised illuminants. order: 16 category: phenomena difficulty: advanced @@ -50,7 +50,7 @@ sections: - Red window (~650–700 nm) - Blue-green window (~450–510 nm) - The stone transmits both simultaneously — this is the structural prerequisite for the + The stone transmits both simultaneously – this is the structural prerequisite for the alexandrite effect. - title: The Photopic Peak and Illuminant Dependence @@ -60,9 +60,9 @@ sections: wavelength range. What remains to dominate the perceived colour depends entirely on illuminant composition: - - **Daylight (D65, ~6500 K)** — strong blue-green component in the illuminant + - **Daylight (D65, ~6500 K)** – strong blue-green component in the illuminant preferentially excites the blue-green transmission window → stone appears green to teal - - **Incandescent (~2700 K, tungsten)** — weak blue, strong red in the illuminant + - **Incandescent (~2700 K, tungsten)** – weak blue, strong red in the illuminant preferentially excites the red transmission window → stone appears red to purplish-red Qiu & Guo (2021) confirmed this mechanism in pyrope-spessartine colour-change garnets: @@ -83,7 +83,7 @@ sections: - title: Named Species table: - caption: Gem species showing the alexandrite effect. [PARTIALLY_SUPPORTED] for diaspore — no DOI-verified primary spectroscopic paper on diaspore colour-change mechanism was retrieved in the source research session; the effect is well-known but the ion assignment relies on standard references [PARTIALLY_SUPPORTED]. + caption: Gem species showing the alexandrite effect. [PARTIALLY_SUPPORTED] for diaspore – no DOI-verified primary spectroscopic paper on diaspore colour-change mechanism was retrieved in the source research session; the effect is well-known but the ion assignment relies on standard references [PARTIALLY_SUPPORTED]. headers: - Species / Variety - Active Ion(s) @@ -94,7 +94,7 @@ sections: - ["Alexandrite (chrysoberyl var.)", "Cr³⁺", "Green to teal", "Red to purplish-red", "Strongest and most complete change known; benchmark for all colour-change gems. Schmetzer & Malsy (2011) [VERIFIED]"] - ["Colour-change garnet (pyrope-spessartine)", "Cr³⁺ + V³⁺", "Blue-green to teal", "Purple to red", "Very strong; best specimens rival alexandrite in completeness. Qiu & Guo (2021) [VERIFIED]"] - ["Colour-change sapphire (corundum)", "V³⁺ (± Cr³⁺)", "Blue to violet", "Purple to red", "Variable; often greyish intermediate colour; locality affects quality"] - - ["Colour-change diaspore ('zultanite', 'csarite')", "V³⁺ + Cr³⁺ (proposed)", "Kiwi green", "Pinkish champagne", "Subtle but characteristic change; spectroscopic assignment [PARTIALLY_SUPPORTED] — no dedicated DOI-verified primary paper retrieved"] + - ["Colour-change diaspore ('zultanite', 'csarite')", "V³⁺ + Cr³⁺ (proposed)", "Kiwi green", "Pinkish champagne", "Subtle but characteristic change; spectroscopic assignment [PARTIALLY_SUPPORTED] – no dedicated DOI-verified primary paper retrieved"] - ["Colour-change synthetic spinel (Co-doped)", "Co²⁺", "Blue-green", "Red-pink", "Common in older synthetic 'alexandrite' simulants; chalky blue-white SW fluorescence distinguishes from alexandrite"] - ["Colour-change fluorite (some)", "[CITATION NEEDED]", "Various", "Various", "Weak; mechanism not confirmed; not diagnostically significant"] @@ -105,7 +105,7 @@ sections: - title: Light Source Requirements content: | - **Daylight equivalent**: D65 fluorescent lamp or north-facing window light (overcast sky). - Avoid mixed LED lighting — LED spectra vary widely and may not reproduce the effect + Avoid mixed LED lighting – LED spectra vary widely and may not reproduce the effect consistently. - **Incandescent**: Standard tungsten bulb (~2700 K). Not LED or halogen at high colour temperature; these do not have sufficient red component to show the full change. @@ -149,7 +149,7 @@ sections: content: | Natural alexandrite: moderate red LWUV fluorescence (Cr³⁺, low-quenching chrysoberyl). Synthetic colour-change spinel simulant: chalky blue-white SW fluorescence (Co²⁺ or - Ti⁴⁺) — completely different response, immediately diagnostic. + Ti⁴⁺) – completely different response, immediately diagnostic. Synthetic alexandrite (Cr-doped) shows similar LWUV red to natural but lacks natural inclusion types; growth features are definitive under magnification. @@ -157,10 +157,10 @@ sections: - title: Sources items: - name: Qiu & Guo (2021) - description: "Explaining Colour Change in Pyrope-Spessartine Garnets. Minerals 11(8), 865. DOI: 10.3390/min11080865. [VERIFIED] — Quantitative UV-Vis spectroscopic confirmation of dual transmission window mechanism; abstract explicitly describes the two transmittance zones and illuminant-dependence." + description: "Explaining Colour Change in Pyrope-Spessartine Garnets. Minerals 11(8), 865. DOI: 10.3390/min11080865. [VERIFIED] – Quantitative UV-Vis spectroscopic confirmation of dual transmission window mechanism; abstract explicitly describes the two transmittance zones and illuminant-dependence." - name: Schmetzer & Malsy (2011) - description: "Alexandrite and colour-change chrysoberyl from the Lake Manyara alexandrite-emerald deposit in northern Tanzania. The Journal of Gemmology 32(5), 179–209. DOI: 10.15506/jog.2011.32.5.179. [VERIFIED] — Detailed optical characterisation of alexandrite; Cr³⁺ as chromophore confirmed." + description: "Alexandrite and colour-change chrysoberyl from the Lake Manyara alexandrite-emerald deposit in northern Tanzania. The Journal of Gemmology 32(5), 179–209. DOI: 10.15506/jog.2011.32.5.179. [VERIFIED] – Detailed optical characterisation of alexandrite; Cr³⁺ as chromophore confirmed." - name: Schmetzer, Bernhardt & Hainschwang (2013) - description: "Titanium-bearing synthetic alexandrite and chrysoberyl. The Journal of Gemmology 33(5), 137–148. DOI: 10.15506/jog.2013.33.5.137. [VERIFIED] — Synthetic alexandrite diagnostics; Ti⁴⁺ absorption differences." + description: "Titanium-bearing synthetic alexandrite and chrysoberyl. The Journal of Gemmology 33(5), 137–148. DOI: 10.15506/jog.2013.33.5.137. [VERIFIED] – Synthetic alexandrite diagnostics; Ti⁴⁺ absorption differences." - name: Read (2008) - description: "Gemmology (3rd ed.). Butterworth-Heinemann/Routledge. DOI: 10.4324/9780080507224. [APPROXIMATE] — Crystal field context and named species survey." + description: "Gemmology (3rd ed.). Butterworth-Heinemann/Routledge. DOI: 10.4324/9780080507224. [APPROXIMATE] – Crystal field context and named species survey." diff --git a/docs/learn/phenomena/aventurescence.yaml b/docs/learn/phenomena/aventurescence.yaml index e6e8c94..28aa437 100644 --- a/docs/learn/phenomena/aventurescence.yaml +++ b/docs/learn/phenomena/aventurescence.yaml @@ -22,7 +22,7 @@ sections: meaning chance), which was discovered accidentally when copper filings fell into molten glass. - The sparkle comes from light reflecting off platy inclusions—typically metallic + The sparkle comes from light reflecting off platy inclusions – typically metallic or reflective mineral flakes oriented within the host crystal. - title: Mechanism diff --git a/docs/learn/phenomena/colour-change.yaml b/docs/learn/phenomena/colour-change.yaml index de59b4d..0f5ecc4 100644 --- a/docs/learn/phenomena/colour-change.yaml +++ b/docs/learn/phenomena/colour-change.yaml @@ -19,7 +19,7 @@ sections: content: | Colour-change gems display different colours under different light sources (typically daylight vs incandescent). The most famous is alexandrite, which - appears green in daylight and red in incandescent light—often described as + appears green in daylight and red in incandescent light – often described as "emerald by day, ruby by night." This phenomenon results from the gem's absorption spectrum interacting @@ -45,7 +45,7 @@ sections: - title: Alexandrite content: | - Alexandrite is colour-change chrysoberyl—the most famous and valuable + Alexandrite is colour-change chrysoberyl – the most famous and valuable colour-change gem. subsections: - title: The Colour Change diff --git a/docs/learn/phenomena/fire-dispersion.yaml b/docs/learn/phenomena/fire-dispersion.yaml index d7b6d34..1d5cfc0 100644 --- a/docs/learn/phenomena/fire-dispersion.yaml +++ b/docs/learn/phenomena/fire-dispersion.yaml @@ -1,5 +1,5 @@ title: Fire and Dispersion -description: Fire in faceted gemstones — dispersion as differential refraction by wavelength, the B–G interval, named dispersion values, relationship to facet design, and distinction from diffraction-based spectral effects. +description: Fire in faceted gemstones – dispersion as differential refraction by wavelength, the B–G interval, named dispersion values, relationship to facet design, and distinction from diffraction-based spectral effects. order: 13 category: phenomena difficulty: intermediate @@ -19,8 +19,8 @@ sections: - title: Definition content: | Fire is the splitting of white light into its spectral colours (red, orange, yellow, green, - blue, violet) visible as coloured flashes in a faceted gemstone. It arises from dispersion — - the variation of refractive index with wavelength — and is enhanced by facet geometry and + blue, violet) visible as coloured flashes in a faceted gemstone. It arises from dispersion – + the variation of refractive index with wavelength – and is enhanced by facet geometry and viewing conditions. Fire is not the same as play-of-colour (opal) or labradorescence: those spectral effects @@ -37,14 +37,14 @@ sections: refracted more strongly at any interface than longer wavelengths (red, orange). This wavelength-dependence of RI is dispersion. When white light enters a gem, each colour component is refracted by a slightly different angle; on exit, the colours emerge at - different positions, producing visible spectral separation — fire. + different positions, producing visible spectral separation – fire. - title: Why Dispersion is Not Diffraction content: | - **Diffraction** involves wave bending around apertures or at periodic structures - (silica sphere arrays in opal, nacre platelet stacks in pearl) — structural colour. + (silica sphere arrays in opal, nacre platelet stacks in pearl) – structural colour. - **Dispersion** involves differential refraction at an interface between two media - of differing refractive index — a bulk optical property of the material. + of differing refractive index – a bulk optical property of the material. Both produce spectral colours but at entirely different physical length scales and by different mechanisms. In a faceted gem, fire is produced at each facet face; in opal, @@ -62,7 +62,7 @@ sections: - title: Named Dispersion Values table: - caption: "B–G dispersion values for selected gem species and simulants. Source: Read (2008) [APPROXIMATE] — no single DOI-verified comprehensive dispersion table was located; diamond, zircon, and moissanite values confirmed across multiple textbook sources. CZ = 0.060 (Read 7th ed. preferred value); do NOT use 0.065 from uncited trade sources." + caption: "B–G dispersion values for selected gem species and simulants. Source: Read (2008) [APPROXIMATE] – no single DOI-verified comprehensive dispersion table was located; diamond, zircon, and moissanite values confirmed across multiple textbook sources. CZ = 0.060 (Read 7th ed. preferred value); do NOT use 0.065 from uncited trade sources." headers: - Species - B–G Dispersion @@ -86,7 +86,7 @@ sections: - title: Facet Design and Fire content: | - Fire is not purely a material property — cut geometry strongly determines how much + Fire is not purely a material property – cut geometry strongly determines how much dispersion is visible: subsections: - title: Cut Geometry @@ -145,6 +145,6 @@ sections: - title: Sources items: - name: Read (2008) - description: "Gemmology (3rd ed.). Butterworth-Heinemann/Routledge. DOI: 10.4324/9780080507224. [APPROXIMATE — chapter confirmed; page references not independently verified] — Primary source for dispersion mechanism and B–G values. No single DOI-verified comprehensive dispersion table paper was located in the source research session; values are textbook-consensus and should be verified against a primary spectrophotometric source before formal examination use. [Confidence C for the full dispersion table]" + description: "Gemmology (3rd ed.). Butterworth-Heinemann/Routledge. DOI: 10.4324/9780080507224. [APPROXIMATE – chapter confirmed; page references not independently verified] – Primary source for dispersion mechanism and B–G values. No single DOI-verified comprehensive dispersion table paper was located in the source research session; values are textbook-consensus and should be verified against a primary spectrophotometric source before formal examination use. [Confidence C for the full dispersion table]" - name: Nassau (2001) - description: "The Physics and Chemistry of Color (2nd ed.). Wiley-Interscience. No DOI retrieved. [UNVERIFIED] — Conceptual support for dispersion mechanism." + description: "The Physics and Chemistry of Color (2nd ed.). Wiley-Interscience. No DOI retrieved. [UNVERIFIED] – Conceptual support for dispersion mechanism." diff --git a/docs/learn/phenomena/fluorescence.yaml b/docs/learn/phenomena/fluorescence.yaml index c9d134a..2c7e13a 100644 --- a/docs/learn/phenomena/fluorescence.yaml +++ b/docs/learn/phenomena/fluorescence.yaml @@ -1,5 +1,5 @@ title: Fluorescence and Phosphorescence -description: Fluorescence and phosphorescence in gemstones — Stokes shift mechanism, LWUV vs SWUV regimes, species reaction table, phosphorescence afterglow, and diagnostic applications for natural vs synthetic identification. +description: Fluorescence and phosphorescence in gemstones – Stokes shift mechanism, LWUV vs SWUV regimes, species reaction table, phosphorescence afterglow, and diagnostic applications for natural vs synthetic identification. order: 12 category: phenomena difficulty: intermediate @@ -32,7 +32,7 @@ sections: Both are distinct from the gem-testing instrument context (UV lamp selection, geometry, box design) covered separately under equipment. - - title: Mechanism — Stokes Shift + - title: Mechanism – Stokes Shift content: | The physical basis of fluorescence: subsections: @@ -40,7 +40,7 @@ sections: content: | When a gem absorbs a UV photon, electrons are promoted to a higher energy level. Before emitting a photon of their own, they lose some energy to lattice vibrations (phonons). - The emitted photon therefore has lower energy — longer wavelength — than the absorbed + The emitted photon therefore has lower energy – longer wavelength – than the absorbed photon. This energy difference is the Stokes shift. Consequence: emitted light is always at longer wavelength (redder) than the exciting @@ -48,11 +48,11 @@ sections: - title: Activators and Chromophores content: | - - **Cr³⁺** — intense red emission ~692–694 nm (ruby R-lines); low-iron corundum - - **N3 centre** (three N atoms + vacancy in diamond) — absorbs at ~415 nm; emits blue (~440–460 nm) under LWUV - - **Mn²⁺** — broad orange-red emission in calcite, scheelite, some fluorites - - **UO₂²⁺ (uranyl ion)** — sharp green bands ~490–570 nm in hyalite opal - - **Ti⁴⁺** — blue emission in Verneuil synthetic spinel (chalky character) + - **Cr³⁺** – intense red emission ~692–694 nm (ruby R-lines); low-iron corundum + - **N3 centre** (three N atoms + vacancy in diamond) – absorbs at ~415 nm; emits blue (~440–460 nm) under LWUV + - **Mn²⁺** – broad orange-red emission in calcite, scheelite, some fluorites + - **UO₂²⁺ (uranyl ion)** – sharp green bands ~490–570 nm in hyalite opal + - **Ti⁴⁺** – blue emission in Verneuil synthetic spinel (chalky character) - title: LWUV vs SWUV Regimes content: | @@ -71,7 +71,7 @@ sections: SWUV reactions often separate natural from synthetic where LWUV cannot. The two lamps test different electronic levels and commonly produce different fluorescence - colours and intensities from the same stone — together they provide a two-point diagnostic. + colours and intensities from the same stone – together they provide a two-point diagnostic. - title: Fluorescence Reactions by Species table: @@ -83,13 +83,13 @@ sections: - Activator / Defect - Notes rows: - - ["Ruby — Mogok (Burma)", "Strong red", "Moderate to strong red", "Cr³⁺", "Low Fe content; minimal quenching; strong LW fluorescence is characteristic of Mogok material (Keller 1983)"] - - ["Ruby — Thai/Cambodian", "Weak to inert", "Inert", "Cr³⁺ quenched by Fe²⁺", "High Fe (>1000 ppm) suppresses Cr³⁺ fluorescence; diagnostic contrast with Mogok"] + - ["Ruby – Mogok (Burma)", "Strong red", "Moderate to strong red", "Cr³⁺", "Low Fe content; minimal quenching; strong LW fluorescence is characteristic of Mogok material (Keller 1983)"] + - ["Ruby – Thai/Cambodian", "Weak to inert", "Inert", "Cr³⁺ quenched by Fe²⁺", "High Fe (>1000 ppm) suppresses Cr³⁺ fluorescence; diagnostic contrast with Mogok"] - ["Flux synthetic ruby (Ramaura, Kashan, Chatham)", "Strong to very strong red", "Strong red", "Cr³⁺ (no Fe quenching in flux growth)", "Often stronger than natural Mogok due to very low Fe; combine with inclusion observation to confirm synthetic"] - - ["Diamond — type Ia (N3)", "Blue to blue-white (strong to moderate)", "Weak to moderate; may show yellow SW", "N3 centre (415 nm)", "Most natural colourless/near-colourless diamonds; LWUV blue is the most common response"] - - ["Diamond — type IIa", "Usually inert", "Usually inert", "No N3; no aggregated N", "Some type IIa show weak blue LWUV; absence of fluorescence combined with high transparency is characteristic"] - - ["Diamond — CVD synthetic", "Inert to weak orange/yellow LW", "Orange, red, or persistent orange-red SW", "NV centres, Si-V, interstitial defects", "Persistent SW phosphorescence is an important diagnostic indicator for CVD — see phosphorescence section below; note: primary peer-reviewed paper for this specific response not yet confirmed [CITATION NEEDED]"] - - ["Diamond — HPHT synthetic", "Yellow-green to inert LW", "Yellow-green SW; may show persistent blue-green phosphorescence", "N-V centre, H3 centre", "Zhu et al. (2024) documented an HPHT diamond with engineered N3-derived blue LW fluorescence mimicking type Ia; requires FTIR confirmation"] + - ["Diamond – type Ia (N3)", "Blue to blue-white (strong to moderate)", "Weak to moderate; may show yellow SW", "N3 centre (415 nm)", "Most natural colourless/near-colourless diamonds; LWUV blue is the most common response"] + - ["Diamond – type IIa", "Usually inert", "Usually inert", "No N3; no aggregated N", "Some type IIa show weak blue LWUV; absence of fluorescence combined with high transparency is characteristic"] + - ["Diamond – CVD synthetic", "Inert to weak orange/yellow LW", "Orange, red, or persistent orange-red SW", "NV centres, Si-V, interstitial defects", "Persistent SW phosphorescence is an important diagnostic indicator for CVD – see phosphorescence section below; note: primary peer-reviewed paper for this specific response not yet confirmed [CITATION NEEDED]"] + - ["Diamond – HPHT synthetic", "Yellow-green to inert LW", "Yellow-green SW; may show persistent blue-green phosphorescence", "N-V centre, H3 centre", "Zhu et al. (2024) documented an HPHT diamond with engineered N3-derived blue LW fluorescence mimicking type Ia; requires FTIR confirmation"] - ["Synthetic spinel (Verneuil)", "Chalky blue-white (intense)", "Chalky green-blue (intense)", "Ti⁴⁺ or related activator", "Highly diagnostic; chalky SW response is the single most reliable indicator of Verneuil synthetic spinel"] - ["Natural spinel (Cr-rich red)", "Orange-red", "Orange", "Cr³⁺", "Moderate to strong; far less intense than the chalky SW response of Verneuil spinel"] - ["Natural emerald (Colombian)", "Inert to very weak red LW", "Inert", "Cr³⁺ quenched by Fe", "Colombian emerald characteristically very weak or inert"] @@ -101,7 +101,7 @@ sections: - ["Scheelite (CaWO₄)", "Bright blue-white LW", "Intense blue-white SW", "W⁶⁺ / Mo⁶⁺", "SW fluorescence is diagnostic for scheelite vs visually similar stones [PARTIALLY_SUPPORTED]"] - ["Benitoite (BaTiSi₃O₉)", "Intense blue LW", "Intense blue SW", "Ti⁴⁺", "Extremely intense blue SW; one of the brightest naturally occurring SW fluorescences known [PARTIALLY_SUPPORTED]"] - ["Calcite", "Red to pink LW", "Red to pink SW", "Mn²⁺", "Useful for detecting calcite in composite stones; many limestone-derived materials fluoresce"] - - ["Pearl (Akoya, cultured)", "Chalky white to blue-white LW", "Variable", "Organic matrix + Mn²⁺", "Weak fluorescence common; treated dark Akoya (gamma-irradiated) may show red LW — treatment indicator"] + - ["Pearl (Akoya, cultured)", "Chalky white to blue-white LW", "Variable", "Organic matrix + Mn²⁺", "Weak fluorescence common; treated dark Akoya (gamma-irradiated) may show red LW – treatment indicator"] - title: Phosphorescence content: | @@ -130,7 +130,7 @@ sections: rows: - ["Hackmanite (sodalite var.)", "Yellow-orange", "Several seconds", "Normal feature of tenebrescence cycle; Kondo & Beaton 2009 [VERIFIED]"] - ["HPHT synthetic diamond", "Blue-green (H3 or N-related)", "Several seconds", "Diagnostic for HPHT type; natural equivalents rare; Zhu et al. 2024 [VERIFIED]"] - - ["CVD synthetic diamond", "Orange to red", "30 s to several minutes", "Highly diagnostic; almost never seen in natural diamonds — note: primary peer-reviewed paper not yet confirmed [CITATION NEEDED]"] + - ["CVD synthetic diamond", "Orange to red", "30 s to several minutes", "Highly diagnostic; almost never seen in natural diamonds – note: primary peer-reviewed paper not yet confirmed [CITATION NEEDED]"] - ["Type IIb natural diamond (boron-bearing)", "Blue", "Several seconds", "Very rare; boron acceptor trap; natural examples confirmed"] - ["ZnS-imitation 'gems'", "Bright green", "Minutes to hours", "Clear indicator of novelty/fake material; ZnS phosphor pigment"] @@ -156,7 +156,7 @@ sections: Most natural diamonds are type Ia and show blue LWUV. Most HPHT synthetics show yellow-green (H3 centre). CVD synthetics frequently show phosphorescence under SWUV. However, Zhu et al. (2024) demonstrated that some HPHT diamonds can be engineered - with N3-derived blue LWUV fluorescence that mimics natural type Ia — requiring + with N3-derived blue LWUV fluorescence that mimics natural type Ia – requiring FTIR confirmation for definitive classification. - title: Iron Quenching Effect @@ -168,14 +168,14 @@ sections: - title: Sources items: - name: Keller (1983) - description: "The Rubies of Burma: A Review of the Mogok Stone Tract. Gems & Gemology 19(4), 209–219. DOI: 10.5741/gems.19.4.209. [VERIFIED] — Documents strong red LWUV fluorescence as characteristic of Mogok ruby." + description: "The Rubies of Burma: A Review of the Mogok Stone Tract. Gems & Gemology 19(4), 209–219. DOI: 10.5741/gems.19.4.209. [VERIFIED] – Documents strong red LWUV fluorescence as characteristic of Mogok ruby." - name: Zhu et al. (2024) description: "A Near-Colourless HPHT-grown Diamond with Natural-appearing Blue Fluorescence from N3 Centres. The Journal of Gemmology 39(1), 24–26. DOI: 10.15506/jog.2024.39.1.24. [VERIFIED]" - name: Zhu et al. (2022) description: "Melee-Sized Colourless HPHT-Grown Synthetic Diamond with Red Fluorescence. The Journal of Gemmology 38(2), 128–129. DOI: 10.15506/jog.2022.38.2.128. [VERIFIED]" - name: Kondo & Beaton (2009) - description: "Hackmanite/Sodalite from Myanmar and Afghanistan. Gems & Gemology 45(1), 38–43. DOI: 10.5741/gems.45.1.38. [VERIFIED] — Hackmanite yellow-orange phosphorescence." + description: "Hackmanite/Sodalite from Myanmar and Afghanistan. Gems & Gemology 45(1), 38–43. DOI: 10.5741/gems.45.1.38. [VERIFIED] – Hackmanite yellow-orange phosphorescence." - name: Radomskaya et al. (2021) - description: "Sulfur-Bearing Sodalite, Hackmanite, in Alkaline Pegmatites of the Inagli Massif. Geology of Ore Deposits 63(7). DOI: 10.1134/s1075701521070060. [VERIFIED] — Hackmanite luminescence and crystal chemistry." + description: "Sulfur-Bearing Sodalite, Hackmanite, in Alkaline Pegmatites of the Inagli Massif. Geology of Ore Deposits 63(7). DOI: 10.1134/s1075701521070060. [VERIFIED] – Hackmanite luminescence and crystal chemistry." - name: Read (2008) - description: "Gemmology (3rd ed.). Butterworth-Heinemann/Routledge. DOI: 10.4324/9780080507224. [APPROXIMATE] — Fluorescence reactions by species; general mechanism." + description: "Gemmology (3rd ed.). Butterworth-Heinemann/Routledge. DOI: 10.4324/9780080507224. [APPROXIMATE] – Fluorescence reactions by species; general mechanism." diff --git a/docs/learn/phenomena/iridescence.yaml b/docs/learn/phenomena/iridescence.yaml index eb21758..78d1dec 100644 --- a/docs/learn/phenomena/iridescence.yaml +++ b/docs/learn/phenomena/iridescence.yaml @@ -19,7 +19,7 @@ sections: content: | Iridescence is a display of spectral colours caused by light interference from thin layers or structures near the surface. Unlike opal's play of colour - (diffraction from spheres), iridescence results from thin-film interference— + (diffraction from spheres), iridescence results from thin-film interference – the same phenomenon that creates colours in soap bubbles and oil slicks. Iridescence appears as rainbow sequences of colour that shift with viewing angle. diff --git a/docs/learn/phenomena/orient.yaml b/docs/learn/phenomena/orient.yaml index 5c7bbde..b0c87ee 100644 --- a/docs/learn/phenomena/orient.yaml +++ b/docs/learn/phenomena/orient.yaml @@ -1,5 +1,5 @@ title: Pearl Orient -description: Pearl orient — the soft iridescent surface bloom of fine nacre, arising from thin-film diffraction and interference at aragonite tablet layers, distinguished from body colour, lustre, and fluorescence. +description: Pearl orient – the soft iridescent surface bloom of fine nacre, arising from thin-film diffraction and interference at aragonite tablet layers, distinguished from body colour, lustre, and fluorescence. order: 14 category: phenomena difficulty: intermediate @@ -24,9 +24,9 @@ sections: the layered aragonite platelet structure of nacre. Orient is entirely distinct from: - - **Body colour** — the dominant saturation and hue of the pearl (white, cream, golden, black) - - **Lustre** — the intensity and quality of the surface reflection - - **Fluorescence** — emission under UV excitation + - **Body colour** – the dominant saturation and hue of the pearl (white, cream, golden, black) + - **Lustre** – the intensity and quality of the surface reflection + - **Fluorescence** – emission under UV excitation A pearl may have high lustre but weak orient (thin nacre), or a deep body colour with strong orient. All four qualities are assessed independently in professional pearl grading. @@ -56,14 +56,14 @@ sections: - title: Distinction from Lustre content: | - Lustre is the quality and intensity of surface reflection — related to the smoothness + Lustre is the quality and intensity of surface reflection – related to the smoothness and translucency of the outermost nacre layers. Orient is the iridescent hue-shifting effect superimposed on lustre. Both depend on nacre quality, but lustre responds to surface smoothness while orient responds to layer periodicity and thickness uniformity. - title: Named Pearl Types and Orient Character table: - caption: Orient characteristics across major pearl types. [PARTIALLY_SUPPORTED] — no single DOI-verified paper comparing orient across all types was retrieved; characteristics are consensus from standard gemmological references (Read 2008) + caption: Orient characteristics across major pearl types. [PARTIALLY_SUPPORTED] – no single DOI-verified paper comparing orient across all types was retrieved; characteristics are consensus from standard gemmological references (Read 2008) headers: - Pearl Type - Mollusc / Species @@ -72,7 +72,7 @@ sections: rows: - ["Akoya", "Pinctada fucata", "~0.4–0.5 µm; relatively uniform", "Delicate rose to green overtone; characteristic 'rosé' overtone prized in Japanese Akoya; quantified by Ozaki et al. 2017 [VERIFIED]"] - ["South Sea", "Pinctada maxima", "Thicker tablets ~0.6–0.8 µm; silver or golden body", "Soft, broad orient; less intense iridescence than Akoya due to thicker layers; very high lustre"] - - ["Tahitian", "Pinctada margaritifera", "Intermediate thickness; dark body", "Peacock orient — green to reddish iridescence over dark body; the characteristic Tahitian overtone"] + - ["Tahitian", "Pinctada margaritifera", "Intermediate thickness; dark body", "Peacock orient – green to reddish iridescence over dark body; the characteristic Tahitian overtone"] - ["Natural seawater", "Various Pinctada spp.", "Variable; often thicker nacre than cultured (years of growth)", "Often strong orient; nacre thickness benefits from longer time in the water"] - ["Freshwater cultured", "Hyriopsis spp.", "Variable; all-nacre (no shell-bead nucleus)", "Improving quality; solid nacre throughout; orient variable depending on processing"] @@ -93,7 +93,7 @@ sections: - title: Freshwater All-Nacre Structure content: | Freshwater cultured pearls (mantle-tissue nucleated, no shell bead) are composed - entirely of nacre. This structure — similar to natural pearls in composition — can + entirely of nacre. This structure – similar to natural pearls in composition – can produce genuine orient, though layer uniformity affects quality. The finest Chinese freshwater pearls increasingly approach Akoya orient quality. @@ -106,7 +106,7 @@ sections: - Pearl-specific? - Test rows: - - ["Orient", "Thin-film diffraction/interference in nacre aragonite layers", "Yes — defining feature of fine nacre", "Visible under ordinary white light; soft multi-tonal iridescence"] + - ["Orient", "Thin-film diffraction/interference in nacre aragonite layers", "Yes – defining feature of fine nacre", "Visible under ordinary white light; soft multi-tonal iridescence"] - ["Body colour", "Organic pigment (porphyrins) + optical depth effects", "Yes", "Colour visible in direct light; does not shift spectrally with angle"] - ["Lustre", "Surface reflectance quality of outermost nacre", "Yes", "Sharpness of reflected image; independent of orient"] - ["Fluorescence", "UV-induced emission (organic matrix + Mn²⁺)", "Yes", "Visible only under UV lamp; inert under ordinary light"] @@ -138,6 +138,6 @@ sections: - title: Sources items: - name: Ozaki et al. (2017) - description: "Calculation of Reflection Spectrum with Actual Layer Thickness Profile in Nacre of Akoya Pearl Oyster. Journal of Physics: Conference Series 924(1), 012011. DOI: 10.1088/1742-6596/924/1/012011. [VERIFIED] — Quantitative structural basis for orient in Akoya pearl." + description: "Calculation of Reflection Spectrum with Actual Layer Thickness Profile in Nacre of Akoya Pearl Oyster. Journal of Physics: Conference Series 924(1), 012011. DOI: 10.1088/1742-6596/924/1/012011. [VERIFIED] – Quantitative structural basis for orient in Akoya pearl." - name: Read (2008) - description: "Gemmology (3rd ed.). Butterworth-Heinemann/Routledge. DOI: 10.4324/9780080507224. [APPROXIMATE] — Pearl orient mechanism, lustre distinction, species characteristics." + description: "Gemmology (3rd ed.). Butterworth-Heinemann/Routledge. DOI: 10.4324/9780080507224. [APPROXIMATE] – Pearl orient mechanism, lustre distinction, species characteristics." diff --git a/docs/learn/phenomena/play-of-colour.yaml b/docs/learn/phenomena/play-of-colour.yaml index db4dd00..3eb50da 100644 --- a/docs/learn/phenomena/play-of-colour.yaml +++ b/docs/learn/phenomena/play-of-colour.yaml @@ -89,7 +89,7 @@ sections: type: info title: Most Valuable Pattern text: | - Harlequin pattern shows angular, mosaic-like patches of colour— + Harlequin pattern shows angular, mosaic-like patches of colour – similar to a clown's costume. Requirements: - Large, distinct colour patches diff --git a/docs/learn/phenomena/schiller.yaml b/docs/learn/phenomena/schiller.yaml index f1d052c..d969f61 100644 --- a/docs/learn/phenomena/schiller.yaml +++ b/docs/learn/phenomena/schiller.yaml @@ -1,5 +1,5 @@ title: Schiller and Peristerescence -description: Schiller and peristerescence in feldspar — the mechanism of non-spectral lamellar scattering, named species, and distinction from adularescence, labradorescence, aventurescence, and chatoyancy. +description: Schiller and peristerescence in feldspar – the mechanism of non-spectral lamellar scattering, named species, and distinction from adularescence, labradorescence, aventurescence, and chatoyancy. order: 10 category: phenomena difficulty: intermediate @@ -27,8 +27,8 @@ sections: The term covers two closely related varieties: - - **Adularescence** — the schiller of orthoclase moonstone (albite lamellae in orthoclase host) - - **Peristerescence** — the schiller of peristerite (albite–oligoclase two-phase plagioclase, An0–An16) + - **Adularescence** – the schiller of orthoclase moonstone (albite lamellae in orthoclase host) + - **Peristerescence** – the schiller of peristerite (albite–oligoclase two-phase plagioclase, An0–An16) Both produce a single-colour (blue or white) billowy glow, wholly distinct from the polychromatic colour play of labradorescence. @@ -60,7 +60,7 @@ sections: content: | Schiller (adularescence/peristerescence) involves non-spectral, single-hue scattering. Labradorescence, by contrast, arises from the Bøggild intergrowth at a specific plagioclase - composition (An47–An58) and produces spectrally selective, polychromatic colour play — + composition (An47–An58) and produces spectrally selective, polychromatic colour play – multiple distinct spectral colours from different zones of the stone. Miura, Tomisaka & Kato (1975) established the relationship between lamellae thickness and @@ -79,7 +79,7 @@ sections: - ["Orthoclase moonstone", "Orthoclase (KAlSi₃O₈)", "Albite exsolution, ~60–150 nm for blue", "Blue to white floating billowy glow; moves with viewing angle"] - ["Sanidine moonstone", "Sanidine (high-T K-feldspar)", "Similar exsolution; higher formation temperature", "White to cream schiller; less common"] - ["Peristerite moonstone", "Albite–oligoclase (An0–An16)", "Two-phase plagioclase; broader lamellae", "Pale blue to white sheen; body colour often darker than orthoclase moonstone"] - - ["'Rainbow moonstone' (trade)", "Labradorite (An~50)", "Bøggild intergrowth — NOT peristerescence", "Multicolour spectral flashes; different mechanism — see labradorescence"] + - ["'Rainbow moonstone' (trade)", "Labradorite (An~50)", "Bøggild intergrowth – NOT peristerescence", "Multicolour spectral flashes; different mechanism – see labradorescence"] - title: Distinguishing from Related Phenomena table: @@ -134,4 +134,4 @@ sections: - name: Krzemnicki (2004) description: "Red and green labradorite feldspar from Congo. The Journal of Gemmology 29(1), 15–23. DOI: 10.15506/jog.2004.29.1.15. [VERIFIED]" - name: Read (2008) - description: "Gemmology (3rd ed.). Butterworth-Heinemann/Routledge. DOI: 10.4324/9780080507224. [APPROXIMATE] — Chapter 'Colour, Lustre and Sheen'; layer-thickness figures and RI values." + description: "Gemmology (3rd ed.). Butterworth-Heinemann/Routledge. DOI: 10.4324/9780080507224. [APPROXIMATE] – Chapter 'Colour, Lustre and Sheen'; layer-thickness figures and RI values." diff --git a/docs/learn/phenomena/silk-effect.yaml b/docs/learn/phenomena/silk-effect.yaml index 53792c1..8e6d774 100644 --- a/docs/learn/phenomena/silk-effect.yaml +++ b/docs/learn/phenomena/silk-effect.yaml @@ -1,5 +1,5 @@ title: Silk Effect -description: The silk effect in Kashmir sapphire and Burmese ruby — velvety appearance from rutile-needle clouds, mechanism, distinction from asterism, and diagnostic significance for origin and heat-treatment detection. +description: The silk effect in Kashmir sapphire and Burmese ruby – velvety appearance from rutile-needle clouds, mechanism, distinction from asterism, and diagnostic significance for origin and heat-treatment detection. order: 11 category: phenomena difficulty: intermediate @@ -46,7 +46,7 @@ sections: preferentially. This diffuses light throughout the stone and reduces the windowing effect that makes some sapphires appear dark from certain angles. - The result is the characteristic cool, hazy blue body appearance of Kashmir sapphire — + The result is the characteristic cool, hazy blue body appearance of Kashmir sapphire – the stone appears illuminated from within. Note: The Rayleigh/Mie scattering assignment is consistent with standard optics for @@ -59,7 +59,7 @@ sections: Heating above approximately 1200 °C dissolves the rutile needles back into the corundum lattice. Loss of silk is therefore one of the primary microscopic indicators of heat treatment in sapphire. Hänni (1990) documented that the characteristic veil-like inclusions - of Kashmir sapphire — which produce its "sleepy or velvety appearance" — are absent or + of Kashmir sapphire – which produce its "sleepy or velvety appearance" – are absent or disrupted in heated material. - title: Named Species @@ -103,8 +103,8 @@ sections: - title: Heat Treatment Indicator content: | - Absence of silk in a sapphire or ruby that would be expected to carry it — particularly - Kashmir and Mogok material — is strong evidence of heat treatment. Labs also look for + Absence of silk in a sapphire or ruby that would be expected to carry it – particularly + Kashmir and Mogok material – is strong evidence of heat treatment. Labs also look for healed fingerprints and absence of needles in stones whose other properties (colour zone, SG, RI) suggest a high-quality natural origin. @@ -121,8 +121,8 @@ sections: - title: Sources items: - name: Hänni (1990) - description: "A contribution to the distinguishing characteristics of sapphire from Kashmir. The Journal of Gemmology 22(2), 67–75. DOI: 10.15506/jog.1990.22.2.67. [VERIFIED] — Primary peer-reviewed reference for Kashmir silk inclusions and velvety appearance." + description: "A contribution to the distinguishing characteristics of sapphire from Kashmir. The Journal of Gemmology 22(2), 67–75. DOI: 10.15506/jog.1990.22.2.67. [VERIFIED] – Primary peer-reviewed reference for Kashmir silk inclusions and velvety appearance." - name: Keller (1983) - description: "The Rubies of Burma: A Review of the Mogok Stone Tract. Gems & Gemology 19(4), 209–219. DOI: 10.5741/gems.19.4.209. [VERIFIED] — Documents inclusion types including silk in Mogok ruby." + description: "The Rubies of Burma: A Review of the Mogok Stone Tract. Gems & Gemology 19(4), 209–219. DOI: 10.5741/gems.19.4.209. [VERIFIED] – Documents inclusion types including silk in Mogok ruby." - name: Read (2008) - description: "Gemmology (3rd ed.). Butterworth-Heinemann/Routledge. DOI: 10.4324/9780080507224. [APPROXIMATE] — Chapter 'Colour, Lustre and Sheen'; silk terminology and heat treatment effects." + description: "Gemmology (3rd ed.). Butterworth-Heinemann/Routledge. DOI: 10.4324/9780080507224. [APPROXIMATE] – Chapter 'Colour, Lustre and Sheen'; silk terminology and heat treatment effects." diff --git a/docs/learn/phenomena/tenebrescence.yaml b/docs/learn/phenomena/tenebrescence.yaml index e53cfcf..cc4bcc8 100644 --- a/docs/learn/phenomena/tenebrescence.yaml +++ b/docs/learn/phenomena/tenebrescence.yaml @@ -1,5 +1,5 @@ title: Tenebrescence -description: Tenebrescence — reversible photochromic colour change in hackmanite driven by S₂⁻ radical colour centres, mechanism, named species, and diagnostic distinction from the alexandrite effect and irradiation-induced colour changes. +description: Tenebrescence – reversible photochromic colour change in hackmanite driven by S₂⁻ radical colour centres, mechanism, named species, and diagnostic distinction from the alexandrite effect and irradiation-induced colour changes. order: 15 category: phenomena difficulty: advanced @@ -26,7 +26,7 @@ sections: in darkness. The effect is driven by the photochemical creation and annihilation of S₂⁻ radical colour - centres within the sodalite framework. It is fully reversible — the same stone can be + centres within the sodalite framework. It is fully reversible – the same stone can be darkened and bleached thousands of times without degradation. - title: Mechanism @@ -35,7 +35,7 @@ sections: subsections: - title: Mineral Chemistry content: | - Hackmanite is the chromatic variety of sodalite — Na₈[Al₆Si₆O₂₄](Cl,S)₂ — in which + Hackmanite is the chromatic variety of sodalite – Na₈[Al₆Si₆O₂₄](Cl,S)₂ – in which some Cl⁻ is replaced by the S₂⁻ disulfide radical anion. The sodalite framework provides cage-like sites (β-cages) that host the color-active sulfur species. @@ -47,7 +47,7 @@ sections: - title: S₂⁻ Colour Centre content: | The S₂⁻ radical anion absorbs visible light around 530–560 nm (yellow-green), giving - the stone its purple/violet appearance — the complementary colour to yellow-green. + the stone its purple/violet appearance – the complementary colour to yellow-green. In the colourless state, sulfur is present in a configuration that does not absorb significantly in the visible range. UV exposure converts some sulfur species to S₂⁻, @@ -62,16 +62,16 @@ sections: content: | After UV exposure, hackmanite shows a yellow-orange persistent afterglow as the excited S₂⁻ centres partially relax via spin-forbidden transitions. This phosphorescence is an - associated feature of the tenebrescence cycle — both arise from the same colour centre. + associated feature of the tenebrescence cycle – both arise from the same colour centre. See also Fluorescence and Phosphorescence for further detail. - title: Reversibility content: | The colour change is fully reversible over thousands of cycles under normal conditions. This distinguishes tenebrescence from: - - Irradiation-induced colour changes (e.g., maxixe beryl, blue topaz) — these are + - Irradiation-induced colour changes (e.g., maxixe beryl, blue topaz) – these are permanent or fade only slowly under prolonged light exposure - - Heat treatment effects — permanent structural changes + - Heat treatment effects – permanent structural changes - title: Named Species table: @@ -82,7 +82,7 @@ sections: - Tenebrescence Character rows: - ["Hackmanite (sodalite var.)", "Myanmar (Sagaing Region), Afghanistan (Badakhshan), Canada (Ontario), Russia (Inagli Massif), Greenland", "Colourless/grey → violet/pink in UV; reverses under incandescent light or warming; primary tenebrescent gem species"] - - ["Tugtupite (beryllosodalite)", "Greenland", "Related photochromic effect; deep red → brighter red under UV; same S₂⁻ mechanism variant [PARTIALLY_SUPPORTED — no separate tugtupite primary paper retrieved]"] + - ["Tugtupite (beryllosodalite)", "Greenland", "Related photochromic effect; deep red → brighter red under UV; same S₂⁻ mechanism variant [PARTIALLY_SUPPORTED – no separate tugtupite primary paper retrieved]"] - ["Some synthetic sodalites", "Laboratory", "Strong engineered tenebrescence; used in persistent luminescence research"] - title: Distinguishing Tenebrescence from the Alexandrite Effect @@ -93,12 +93,12 @@ sections: - Tenebrescence - Alexandrite Effect rows: - - ["Reversibility", "Fully reversible by light or mild heat", "Reversible in the same sense — colour shifts immediately with light source change"] + - ["Reversibility", "Fully reversible by light or mild heat", "Reversible in the same sense – colour shifts immediately with light source change"] - ["Cause", "Photochemical creation/destruction of S₂⁻ colour centre", "Fixed Cr³⁺ (or V³⁺) absorption window; colour depends on illuminant spectral power"] - - ["UV activation required?", "Yes — UV or short-wavelength visible light triggers the colour state", "No — colour change is passive, driven by visible illuminant composition only"] + - ["UV activation required?", "Yes – UV or short-wavelength visible light triggers the colour state", "No – colour change is passive, driven by visible illuminant composition only"] - ["Mineral group", "Sodalite group (tectosilicate)", "Chrysoberyl (alexandrite), garnet, sapphire, diaspore"] - ["State persistence", "Coloured state persists in darkness until reversed by visible light or heat", "Colour reverts immediately when illuminant changes; no residual state"] - - ["Test lamp needed?", "Yes — SWUV lamp to induce colour", "No — observe under daylight and incandescent only"] + - ["Test lamp needed?", "Yes – SWUV lamp to induce colour", "No – observe under daylight and incandescent only"] - title: How to Test for Tenebrescence content: | @@ -106,12 +106,12 @@ sections: subsections: - title: Test Procedure content: | - 1. Observe the stone under incandescent or ambient light — note colourless to pale grey + 1. Observe the stone under incandescent or ambient light – note colourless to pale grey body colour. 2. Illuminate with shortwave UV (SWUV, 254 nm) for 10–30 seconds in subdued conditions. - 3. Remove UV source and observe immediately under incandescent light — dramatic violet + 3. Remove UV source and observe immediately under incandescent light – dramatic violet to purple colour should be visible. - 4. Leave in ordinary light or warm gently — colour fades to near-colourless within + 4. Leave in ordinary light or warm gently – colour fades to near-colourless within seconds to minutes. The effect is instantaneous and dramatic in fine material. Even in weak hackmanite, @@ -134,17 +134,17 @@ sections: - Distinguish from irradiation-induced colour changes (e.g., maxixe beryl, blue topaz, treated pink diamonds): irradiation-induced colours do not reverse under ordinary - daylight exposure — they are permanent or fade only under prolonged high-intensity light + daylight exposure – they are permanent or fade only under prolonged high-intensity light or high temperature. - - Hackmanite also shows yellow-orange phosphorescence after UV excitation — a feature + - Hackmanite also shows yellow-orange phosphorescence after UV excitation – a feature confirmed by both Kondo & Beaton (2009) and Radomskaya et al. (2021). - title: Sources items: - name: Kondo & Beaton (2009) - description: "Hackmanite/Sodalite from Myanmar and Afghanistan. Gems & Gemology 45(1), 38–43. DOI: 10.5741/gems.45.1.38. [VERIFIED] — Primary gemmological source for tenebrescence in hackmanite; documents colour change, phosphorescence, and locality characteristics." + description: "Hackmanite/Sodalite from Myanmar and Afghanistan. Gems & Gemology 45(1), 38–43. DOI: 10.5741/gems.45.1.38. [VERIFIED] – Primary gemmological source for tenebrescence in hackmanite; documents colour change, phosphorescence, and locality characteristics." - name: Goettlicher et al. (2013) - description: "Sulfur K X-ray absorption near edge structure spectroscopy on the photochrome sodalite variety hackmanite. Zeitschrift für Kristallographie – Crystalline Materials 228(3), 157–171. DOI: 10.1524/zkri.2013.1587. [VERIFIED] — Confirms S₂⁻ radical as photochromic agent via XANES." + description: "Sulfur K X-ray absorption near edge structure spectroscopy on the photochrome sodalite variety hackmanite. Zeitschrift für Kristallographie – Crystalline Materials 228(3), 157–171. DOI: 10.1524/zkri.2013.1587. [VERIFIED] – Confirms S₂⁻ radical as photochromic agent via XANES." - name: Radomskaya et al. (2021) - description: "Sulfur-Bearing Sodalite, Hackmanite, in Alkaline Pegmatites of the Inagli Massif. Geology of Ore Deposits 63(7). DOI: 10.1134/s1075701521070060. [VERIFIED] — Crystal chemistry, photochromism, and luminescence of Russian hackmanite." + description: "Sulfur-Bearing Sodalite, Hackmanite, in Alkaline Pegmatites of the Inagli Massif. Geology of Ore Deposits 63(7). DOI: 10.1134/s1075701521070060. [VERIFIED] – Crystal chemistry, photochromism, and luminescence of Russian hackmanite." diff --git a/docs/learn/species/amphibole.yaml b/docs/learn/species/amphibole.yaml index 9a25322..f718029 100644 --- a/docs/learn/species/amphibole.yaml +++ b/docs/learn/species/amphibole.yaml @@ -69,7 +69,7 @@ sections: text: | Nephrite's interlocking fibrous structure makes it tougher than steel. This exceptional toughness made it valuable for prehistoric tools and - weapons—the name "jade" comes from Spanish "piedra de ijada" (stone + weapons – the name "jade" comes from Spanish "piedra de ijada" (stone of the side), referring to its supposed healing properties. Archaeological nephrite axes show minimal damage despite heavy use. @@ -118,7 +118,7 @@ sections: title: Hetian Jade text: | White nephrite from Hetian (Khotan) in Xinjiang, China, is the most - valued jade in Chinese culture—more so than green jadeite. Called + valued jade in Chinese culture – more so than green jadeite. Called "mutton fat jade" for its warm, creamy appearance, fine Hetian nephrite has been treasured for over 5,000 years. diff --git a/docs/learn/species/beryl.yaml b/docs/learn/species/beryl.yaml index a6536ed..991c1ac 100644 --- a/docs/learn/species/beryl.yaml +++ b/docs/learn/species/beryl.yaml @@ -81,7 +81,7 @@ sections: - title: The Jardín content: | - Emeralds are expected to have inclusions—the French word "jardín" (garden) + Emeralds are expected to have inclusions – the French word "jardín" (garden) describes the typical internal landscape: - Inclusions are more accepted than in other gems diff --git a/docs/learn/species/chrysoberyl.yaml b/docs/learn/species/chrysoberyl.yaml index 8cb69d5..d3e82ab 100644 --- a/docs/learn/species/chrysoberyl.yaml +++ b/docs/learn/species/chrysoberyl.yaml @@ -156,7 +156,7 @@ sections: - title: Nomenclature content: | - Only chrysoberyl may be called simply "cat's eye"—all other + Only chrysoberyl may be called simply "cat's eye" – all other chatoyant gems require qualification: - "Cat's eye" = chrysoberyl cat's eye diff --git a/docs/learn/species/feldspar.yaml b/docs/learn/species/feldspar.yaml index b7c028b..0f3aed4 100644 --- a/docs/learn/species/feldspar.yaml +++ b/docs/learn/species/feldspar.yaml @@ -59,7 +59,7 @@ sections: - title: Moonstone content: | - Moonstone displays adularescence—a soft, billowy glow that appears to float + Moonstone displays adularescence – a soft, billowy glow that appears to float just below the surface. subsections: - title: Cause of Adularescence @@ -110,7 +110,7 @@ sections: - title: Labradorite content: | - Labradorite displays labradorescence—striking plays of colour including + Labradorite displays labradorescence – striking plays of colour including blue, green, gold, and purple. subsections: - title: Cause of Labradorescence @@ -142,7 +142,7 @@ sections: - title: Sunstone content: | - Sunstone displays aventurescence—a glittery, metallic reflection from + Sunstone displays aventurescence – a glittery, metallic reflection from included platelets. subsections: - title: Cause of Aventurescence diff --git a/docs/learn/species/garnet.yaml b/docs/learn/species/garnet.yaml index f6acbb7..436f94b 100644 --- a/docs/learn/species/garnet.yaml +++ b/docs/learn/species/garnet.yaml @@ -166,7 +166,7 @@ sections: - **RI**: ~1.88; **SG**: ~3.85 - **Dispersion**: 0.057 (higher than diamond!) - **Spectrum**: Cr line at 443nm ("horse line") - - **Sources**: Russia (Ural—finest), Namibia, Madagascar + - **Sources**: Russia (Ural – finest), Namibia, Madagascar - title: Horsetail Inclusions content: | diff --git a/docs/learn/species/olivine.yaml b/docs/learn/species/olivine.yaml index 30a7f6e..8190efe 100644 --- a/docs/learn/species/olivine.yaml +++ b/docs/learn/species/olivine.yaml @@ -65,7 +65,7 @@ sections: type: info title: Diagnostic Inclusion text: | - Peridot is famous for "lily pad" inclusions—disc-shaped stress fractures + Peridot is famous for "lily pad" inclusions – disc-shaped stress fractures surrounding tiny chromite crystals. These appear as small round "explosions" when viewed under magnification. @@ -96,7 +96,7 @@ sections: it "the gem of the sun." The mines are now exhausted. Interestingly, "Topazios," the Greek name for this island, is where - the word "topaz" originated—though the island produced peridot, not topaz. + the word "topaz" originated – though the island produced peridot, not topaz. - title: Characteristic Inclusions content: | diff --git a/docs/learn/species/opal.yaml b/docs/learn/species/opal.yaml index bec1995..d80d833 100644 --- a/docs/learn/species/opal.yaml +++ b/docs/learn/species/opal.yaml @@ -52,7 +52,7 @@ sections: - title: Play of Colour content: | - Play of colour is opal's defining phenomenon—flashing spectral colours + Play of colour is opal's defining phenomenon – flashing spectral colours that shift as the stone moves. subsections: - title: Cause @@ -131,7 +131,7 @@ sections: type: info title: Most Prized Pattern text: | - Harlequin pattern—angular, mosaic-like patches of colour—is the most + Harlequin pattern – angular, mosaic-like patches of colour – is the most valuable opal pattern. A true harlequin black opal can command extraordinary prices, with exceptional examples selling for hundreds of thousands of dollars. @@ -158,7 +158,7 @@ sections: type: warning title: Hydrophane Behaviour text: | - Ethiopian opal is often hydrophane—it absorbs water, becoming more + Ethiopian opal is often hydrophane – it absorbs water, becoming more transparent when wet and returning to original appearance when dry. Concerns include: diff --git a/docs/learn/species/pearl.yaml b/docs/learn/species/pearl.yaml index 1b1b222..d78a989 100644 --- a/docs/learn/species/pearl.yaml +++ b/docs/learn/species/pearl.yaml @@ -23,7 +23,7 @@ sections: the most commercially important organic gems and the only gems created by living creatures. - Nearly all pearls in today's market are cultured—human-initiated by inserting + Nearly all pearls available now are cultured – human-initiated by inserting a bead nucleus or tissue. Natural pearls are extremely rare and primarily found in antique jewellery. diff --git a/docs/learn/species/pyroxene.yaml b/docs/learn/species/pyroxene.yaml index dff3a78..11f71a4 100644 --- a/docs/learn/species/pyroxene.yaml +++ b/docs/learn/species/pyroxene.yaml @@ -19,7 +19,7 @@ sections: - title: Introduction content: | The pyroxene group is a family of chain silicates that includes several - important gem materials. Jadeite is the most valuable—one of the two + important gem materials. Jadeite is the most valuable – one of the two minerals called "jade." Spodumene produces kunzite and hiddenite, while chrome diopside offers affordable green colour. @@ -76,7 +76,7 @@ sections: type: info title: Exceptional Prices text: | - Top-quality Imperial jade can command extraordinary prices—fine + Top-quality Imperial jade can command extraordinary prices – fine cabochons have sold for over $3 million per carat at auction. The combination of vivid green colour, good transparency, and fine texture in large pieces is exceptionally rare. diff --git a/docs/learn/species/quartz.yaml b/docs/learn/species/quartz.yaml index 156f64d..6358eb4 100644 --- a/docs/learn/species/quartz.yaml +++ b/docs/learn/species/quartz.yaml @@ -22,8 +22,8 @@ sections: most versatile gem materials. It occurs in two main forms: macrocrystalline (visible crystals) and cryptocrystalline (chalcedony varieties). - Despite its commonality, fine quartz specimens—particularly amethyst and - well-coloured citrine—remain popular and valuable. + Despite its commonality, fine quartz specimens – particularly amethyst and + well-coloured citrine – remain popular and valuable. - title: Mineralogy subsections: diff --git a/docs/learn/species/spinel.yaml b/docs/learn/species/spinel.yaml index 8ef22a7..807af13 100644 --- a/docs/learn/species/spinel.yaml +++ b/docs/learn/species/spinel.yaml @@ -22,7 +22,7 @@ sections: prized gem in its own right, with fine red and cobalt-blue specimens commanding exceptional prices. - The "great impostors" of history—the Black Prince's Ruby and Timur Ruby—are + The "great impostors" of history – the Black Prince's Ruby and Timur Ruby – are both red spinels, testament to their beauty rivaling ruby. - title: Mineralogy @@ -101,7 +101,7 @@ sections: The vivid, saturated blue with no heat treatment commands prices exceeding $10,000 per carat for fine examples. - True cobalt colour must be confirmed by spectroscopy—iron-blue + True cobalt colour must be confirmed by spectroscopy – iron-blue spinels are much less valuable. - title: Major Sources @@ -187,7 +187,7 @@ sections: text: | Natural spinel may show some ADR (anomalous double refraction) under the polariscope, but synthetic flame-fusion spinel typically shows - much stronger, more pronounced ADR—a useful distinguishing feature. + much stronger, more pronounced ADR – a useful distinguishing feature. The "tabby extinction" pattern in synthetic spinel is often more dramatic than in natural material. @@ -207,7 +207,7 @@ sections: content: | Key features for spinel identification: - - **RI**: 1.718 (single reading—isotropic) + - **RI**: 1.718 (single reading – isotropic) - **SG**: 3.60 - **Optic character**: SR (stays dark in polariscope, or shows ADR) - **No pleochroism**: No colour change in dichroscope diff --git a/docs/learn/species/tourmaline.yaml b/docs/learn/species/tourmaline.yaml index 4c659d6..c1e0922 100644 --- a/docs/learn/species/tourmaline.yaml +++ b/docs/learn/species/tourmaline.yaml @@ -140,7 +140,7 @@ sections: - title: Identification content: | - - Must contain copper (Cu)—verified by chemical analysis + - Must contain copper (Cu) – verified by chemical analysis - Geographic origin requires trace element ratios (Cu/Mn, Ga, Pb) - Inclusions less diagnostic than for other gems - Lab certification essential for high-value stones diff --git a/docs/learn/species/zircon.yaml b/docs/learn/species/zircon.yaml index 7f65cca..7aecd06 100644 --- a/docs/learn/species/zircon.yaml +++ b/docs/learn/species/zircon.yaml @@ -19,7 +19,7 @@ sections: content: | Zircon (ZrSiO₄) is a zirconium silicate with exceptional brilliance and dispersion. Often confused with cubic zirconia (CZ), natural zircon is a - completely different material—one of the oldest minerals on Earth, with + completely different material – one of the oldest minerals on Earth, with specimens dating back 4.4 billion years. The December birthstone in its blue form, zircon offers diamond-like diff --git a/docs/learn/species/zoisite.yaml b/docs/learn/species/zoisite.yaml index ef4a76b..f6e61f7 100644 --- a/docs/learn/species/zoisite.yaml +++ b/docs/learn/species/zoisite.yaml @@ -18,8 +18,8 @@ sections: - title: Introduction content: | Zoisite (Ca₂Al₃(SiO₄)₃(OH)) is a calcium aluminium silicate that produces - several gem varieties. Tanzanite—the blue-violet variety found only in - Tanzania—is by far the most important, having become one of the world's + several gem varieties. Tanzanite – the blue-violet variety found only in + Tanzania – is by far the most important, having become one of the world's most popular coloured gemstones since its discovery in 1967. - title: Mineralogy