This calcite crystal cluster is from the Tsumeb Mine, Tsumeb, Otjikoto Region of Namibia. This is an ore pipe deposit that is mined for copper lead and other metals. It is over 3000 feet deep and contains two oxidation zones. Over 300 mineral species have been identified at the mine. One of the gangue minerals is calcite. This is a rosette type formation of well defined calcite crystals with a thin reticulated remnant matrix on the rear surface. The crystals are translucent and colorless to white in color. They have a bright vitreous luster. This piece measures 2 5/8 x 2 1/16 x 1 1/4 inches or 66 x 51 x 32.