The Minecraft Emerald is the Ancient Currency of an Ancient Race.

The Villagers. While no-one knows exactly what they do with these iconic gemstones, there must be some sort of magic underlying- after all, they are willing to trade you other items of extreme value for just for a few of these, such as carro- I mean, enchanted books and tools.

That leads me to post these here, where you too can collect these gems and discover their hidden potential.

(Or just hold them.)