Dioptase is a beautiful, vivid emerald-green, having a hint of blue. It has very high fire, but this is masked by its strong color, which may make stones translucent rather than transparent. Prized by the collector for its colour, it is nonetheless rarely faceted, as stones are brittle and fragile, and too soft to be worn. It is sometime wrongly identified as emerald.
The best quality dioptase is found in copper deposits in Russia, Namibia, Zaire, Chile, and Arizona (USA).