Dec value: 388
Hex value: 184
Maximum stack 64
Emeralds are obtained by either mining the extremely rare emerald ore, or by trading items with villagers. They currently only serve one purpose, which is as a currency.
Villagers will sell you a variaty of items for various amounts of emeralds. This is a nice way to spend any emeralds you may have found, though it’s generally not really worth it to farm the emeralds specifically to trade, as it’s a lot easier to simply get the items yourself. However, blacksmith villagers do sell chainmail armour, which is otherwise unobtainable.