Dioptase from Tsumeb

Dioptase is an uncommon mineral that forms as a secondary mineral in the oxidized zone of copper sulfide mineral deposites. It's typicall found in desert regions including at Tsumeb in Namibia, and Reneville in Congo-Brazzaville. It ranges from intense emerald-green to bluish-green. Neolithic statues dating back to 7200 B.C. have been discovdered that used dioptase for decoration.