Gem Dragon
Gem Dragons are a family of dragon in the multiverse of Dungeons & Dragons, and during the days of Advanced Dungeons & Dragons made up the oft-forgotten "third" of the great dragon families, alongside Metallic Dragons and Chromatic Dragons. Gem Dragons are defined predominantly by their allegiance to Neutrality, in comparison to the Goodly Metallics and the Evil Chromatics.
Gem Dragons are divided into two sub-families. The "true" Gem Dragons are based on crystalline precious stones and, uniquely amongst dragons of the time, wield psionics. "Lesser" Gem Dragons (officially called "Neutral Dragons", but come on, that's a stupid name) are based on semi-precious stones and lack the psionic powers of their kinsfolk.
These dragons have languished in obscurity since the coming of 3rd edition.