This specimen is a very attractive, incredibly rare, superb quality, crystallized specimen of the triclinic lead, antimony, iron, tin sulfosalt Potosiite consisting of several, extremely rare, highly lustrous, heavily striated, tabular blades (some are twinned) of Potosiite measuring up to 6 mm sitting atop crystallized and the equally rare triclinic lead, tin, iron, antimony sulfosalt Franckeite. For those of you who are unaware, the crystals of Potosiite on this specimen are EXCEPTIONALLY LARGE for the species.