Emerald Tier adds a new tier of weapons, tools, and armor to Minecraft, balanced around a vanilla play experience. Overall, emerald gear is slightly weaker than diamond gear, and moderately less durable. Emerald tier items, however, are much more enchantable than diamond or netherite.
The emerald horse armor provides slightly more armor than diamond horse armor. This is balanced around the fact that vanilla gold horse armor offers more protection than iron horse armor, to make up for the lack of horse armor enchants. This cannot be crafted, but can be found in most places diamond horse armor can.