Mottramite in big botryoidal masses occurs in few places, Tsumeb the most well known. This is a large, showy cluster of "worms" of rounded mottramite growths covering an ore matrix. Despite its size, it is nearly pristine (with just one spot of damage on the backside, as shown). It has a matte evergreen-colored surface, and is unusually richly covered. In fact, I have not seen one quite like this, but for smaller sizes. An old piece, once donated to the University of Arizona Mineral Museum.