San Jose Mine, Oruro City, Cercado Province, Oruro Department, Bolivia
Toenail, 3.0 x 2.7 x 2.2 cm
These specimens came out of this mine around 2006 and are among some of my favorite "new finds" from Bolivia. This piece features rather large, semi-lustrous, sharp, dark silvery colored, twinned crystals of the rare copper iron tin sulfide Stannite which are associated with minor Zinkenite. The Stannite crystals are virtually as large as individual crystals of Stannite get from any locality in Bolivia. There were only a handful of these specimens and they are superior to most Stannite from China because the Chinese crystals are sometimes composite crystal groups consisting of many smaller crystals to form a larger aggregate, and nowhere else besides this find have I ever seen twinned Stannite crystals like these.