Calcite with Pyrolusite

Sharp, sugary-white Calcite forms an open cluster of rhombohedral crystals of varying size, ranging from just a few mm to 2.2 cm on edge.  From the Tsumeb mine in Namibia, the crystals have a sucrosic texture which give a matt, non-reflective lustre.  The purity of the snow-white Calcite is interrupted on occasional crystals by blackened areas smudged with micro-crystalline Pyrolusite, manganese dioxide.  Despite being common throughout all levels at Tsumeb, it is a species not readily recognised or recorded on specimens, so making this a nice addition to a Tsumeb suite.