Graygem
The Graygem or Graystone is a powerful ancient artifact in the D&D setting of Dragonlance. It is said to be responsible for the creation of many different races and monsters via magical mutation.
The trickster god Hiddukel tricked the Dwarven god Reorx into forging the Graygem. It was then placed on the moon Lunitari for safekeeping, where it stayed until a Tinker Gnome, in true gnomish fashion, invented a Self-Propelled Lunar Extension Ladder, allowing him to climb up to the moon and steal the jewel. No really, we're not kidding. Unfortunately, the gnome lost his grip on the Graygem as he was climbing back down and the jewel fell down to Krynn, where it caused all sorts of mischief by radiating powerful chaos magic.