- The Corundum Crystal is a limited decoration. Currently this decoration is expired and can no longer be bought at the market.
- The Corundum Crystal was added to the market on July 1, 2012, along with the Ruby Dragon.
- The Corundum Crystal left the market on August 1, 2012.
- On December 18, 2012, the Corundum Crystal, and all other expired limited dragons and decorations, returned to the market as part of the "Bring 'Em Back" event.
- The event was scheduled to end on January 2, 2013, but was extended; the expired limited dragons and decorations left on January 14, 2013.
- The Corundum Crystal does NOT increase your chances of breeding a Ruby Dragon.
- Corundum is the mineral of which rubies are comprised.