Dioptase

Fine dioptase on dolomite from the world-famous Tsumeb Mine, Otavi Highlands, Namibia. The specimen displays vivid emerald-green dioptase crystals forming sharp, well-developed prismatic individuals set on a contrasting white to colourless dolomite matrix. The strong colour saturation and crystal definition are characteristic of classic high-quality Tsumeb material.

Dioptase is a copper silicate mineral, first described in 1797 by René Just Haüy, who named the species from the Greek dia (through) and optos (visible), referring to the visibility of cleavage directions through the crystal. Dioptase forms as a secondary mineral in the oxidation zone of copper deposits, often under arid to semi-arid conditions.

The Tsumeb Mine is one of the world’s most important and celebrated localities for dioptase and has produced some of the finest specimens known. Well-crystallized dioptase on contrasting carbonate matrix is considered classic Tsumeb material and is highly sought after by collectors. At this locality, dioptase is typically associated with dolomite, which forms the characteristic matrix seen in many reference specimens.

The specimen originates from the former collection of C. Strömpl, an amateur mineralogist.