Treasure 2 adds a new and exciting element to Minecraft… Treasure! All around your world you’ll now be able to discover buried treasure, usually found beneath cemeteries. Some of them may be locked and some may be wide open for the taking.
Once you find one chest, you may be given keys to find other chests. Hovering over the keys will tell you the rarity of the chest they will open. And then when you find a chest with a corresponding key, just hold shift while right-clicking and the lock comes off.