Dims: 3.9 x 3.2 x 2.0" (9.9 x 8.1 x 5.1 cm)
Wt: 1 lb., 0.5 oz. (467 g)
Tsumeb Mine, Tsumeb, Namibia
This specimen consists of dozens of arborescent Mottramite formations that are intergrown and partly embedded in a calcite base. Most of the formations are damaged or incomplete and their intergrowth makes them difficult to effectively measure, but where intact they seem to be well-formed. The formations branch off to form crystals that have well-defined edges and clean faces. All appear to have a dull olive-green coloration on their intact surfaces, whereas damaged surfaces show a darkgray color. Oddly enough, these damaged areas show a submetallic luster that is duller than that of the intact surfaces, which have a very bright pearly-to-vitreous shine. All are well embedded into the calcite base, which is made up of many intergrown trigonal crystals, most of which show at least slight damage.