style(lang): British English compliance and AI-tell removal across learn content

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

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
@@ -151,25 +151,25 @@ 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
           elemental analysis down to ppm levels for elements with atomic number ≥ 11 (sodium).
 
           - 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

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
@@ -84,48 +84,48 @@ 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
     callout:
       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]