Calcite

The diversity of Calcite at Tsumeb is seemingly never ending, be this habit, colour or associated mineralogy, a direct consequence of a calcium and carbonate-rich system.  This cabinet specimen has a pale brick-red and mid-grey Dolomite matrix entirely enveloped over its upper surface with equant colourless, to off milky-white nail-head Calcite crystals ranging from 0.5 to 1.4 cm across.  The smaller crystals tend to be more transparent with a glassy lustre whereas the larger become more translucent with a duller, more greasy lustre.  Very often each crystal contains a dark grey granular inclusion, frequently close to the crystal’s surface and its pyramidal termination.  The base is interesting also, because the greyish-pink Dolomite nodular core is edged by an opaque apple-green coating of probable duftite.  A great Calcite from Tsumeb.