Calcite on Conichalcite

A classic specimen of beautiful rhombohedral, sharp-edged crystals of Calcite set against a carpet of rich leaf-green Conichalcite from the Tsumeb Mine in the Oshikoto Region of Namibia. The Calcite crystals have developed as equant (equal-sided) rhombs and as flattened, more tabular rhombs. Although essentially colourless, all crystals are tinted a greyish-cream, especially towards their centres. The prism faces are glassy-smooth and mirror-bright and at certain angles give a play of iridescent interference colours from both their surface and internally.  The Calcite rhombs also catch the light giving superb internal reflections, making them appear backlit. The solid, iron-stained Dolomite matrix naturally positions the display face at one of either two angles, according to which side of the base the specimen rests on. The Conichalcite forms a solid covering of sub-mm botryoidal crystal aggregates which provide a velvety backdrop to the Calcite. A Tsumeb classic.