A choice thumbnail displaying a single equant crystal of Dioptase on a small bed of millimetre-sized, naturally etched Calcite crystals from the Tsumeb mine in Namibia. The Dioptase crystal measures 1 cm across at its widest point and is a translucent deep emerald green. Dioptase, a copper silicate, is one of, if not the, most iconic minerals from Tsumeb. This specimen comes mounted on a small clear acrylic base.