Crystals

Crystals are items in the form of Lapis Lazuli that can be traded for items with the crystal trader at spawn.

Some of the items that can be traded for include:

Pickaxes that have a one time use to miner the spawner specified in the description.

A single Spawn egg for a mob

Various custom items

MCMMO Books (right click to gain a MCMMO credit)

Other random things