This is a fabulous mini of Tsumeb tarnowitzite (lead-rich variety of aragonite, technically a mixture of aragonite and cerussite) - made really special by the presence of a LARGE single crystal with fantastic sharp form, next to a smaller one, in a bend in the matrix that showcases it perfectly. Tarnowitzite specimens can be fairly clunky, but this one is really aesthetic. Ex. Willy Israel and Sid Pieters Collections.