I read on one of the Reddits how Mojang devs have said that they'll never add a currency because it makes Emeralds pointless. While I have provided a trade option for Emeralds I would like to try and come up with something more than what's already offered in the mod market for Emeralds (like Armor).

Ideas:

• Enchanting stones that can be used like enchanted books
• Enchanting stones that can be slotted into armor/weapons/and tools
• Enchanting stones that can be consumed by the player for a permanent boost to player stats, like health.
• Place Emerald on "Enchanting Altar" over-night with sky access to turn the Emerald into an "Enchanted Emerald" with a random stat bonus that can be applied to weapons, tools, and armor.