Dioptase on Calcite (copper silicate and calcium carbonate)

This specimen shows a group of well-shaped rhombohedral pearly-white calcite crystals with a liberal scattering of sugary emerald green dioptase crystals. Dioptase is an uncommon copper mineral prized for its intense green colour. It is found in only a few copper mines world-wide, but the best examples have come from Namibia.