- Franckeite (Var: Potosiite), Franckeite
- Small Cabinet, 6.6 x 3.7 x 2.6 cm
- San Jose Mine, Oruro City, Cercado Province, Oruro Department, Bolivia
From the new find of 2004, this specimen hosts two of the rarest sulfosalts in the world. This specimen is a very attractive, very rare, superb quality, crystallized specimen of the triclinic lead, antimony, iron, tin sulfosalt Potosiite consisting of extremely rare, highly lustrous, heavily striated, tabular blades (some are twinned) of Potosiite measuring up to 13 mm sitting atop crystallized and the equally rare triclinic lead, tin, iron, antimony sulfosalt Franckeite. The crystals of Potosiite on this specimen are exceptionally large for the species. This new find has completely redefined the species of Potosiite.