- Franckeite (Var: Potosiite), Franckeite
- San Jose Mine, Oruro City, Cercado Province, Oruro Department, Bolivia
- Small Cabinet, 5.8 x 4.4 x 3.5 cm
From the great find of 2004. This specimen is a very attractive, incredibly rare, superb, crystallized specimen Potosiite consisting of several, extremely rare, highly lustrous, heavily striated, tabular blades (some are twinned) measuring up to 7 mm sitting atop a crystallized mound of the rare triclinic lead, tin, iron, antimony sulfosalt Franckeite. The crystals of Potosiite on this specimen are exceptionally large. Before these new specimens were discovered, some of the largest known crystals of Potosiite were massive, uncrystallized granules less than 1 mm in most cases.