Potosiite and franckeite are RARE sulfosalts. This is a SUPERB and very RICH, pristine specimen of radial clusters of lathe-shaped potosiite blades to 4 mm totally covering starburst-shaped clusters of lustrous, elongated franckeite blades. This is from 2 years ago, some small finds at the San Jose Mine of Bolivia in the same part of the mine (mining out pillars) where they found potosiite some 60 years ago.