Miner
From EZ Server Wiki
You can turn in two Minor Rainbow Crystals to the Miner for a chance to make a Greater Rainbow Crystal - or two Lesser Rainbow Crystals for a chance to make a Major Rainbow Crystal. The chance of success is approximately 33%. If you fail then turnin, you receive one of the two original crystals back.
Minor Rainbow Crystal 2,000 AA's Lesser Rainbow Crystal 4,000 AA's Greater Rainbow Crystal 10,000 AA's Major Rainbow Crystal 20,000 AA's