Dioptase is a gorgeous, intense green mineral that forms in desert regions as a secondary mineral. It has a hardness of 5 and its chemical formula is CuSiO3·H2O. A fun fact is that human tooth enamel has a hardness of 5 as well, but do not test it at home because the mineral will probably win! It forms beautiful, rhombohedral crystals with pointed ends.

Minerals are made of elements which bond together in a specific chemical structure. Often in this structure, there will be certain chemical bonds that are weaker than others. So, when a mineral breaks, it will break along those planes of weakness. This is called cleavage, and dioptase has 3 perfect cleavages.The name dioptase is Greek and means to “see through.” This refers to the ability to see the mineral’s cleavage planes in unbroken and translucent specimens.

Dioptase is very popular, but because it is so soft, it does not make long-lasting jewelry. The best specimens in the world come from Tsumeb Mine in Northern Namibia. We have quite a few specimens of dioptase in the mineral museum, including one in our green case, so come on by!