- Poopo town, Poopo Province, Oruro Department, Bolivia
- Small Cabinet, 6.5 x 4.1 x 3.4 cm
Cylindrite is a lead, iron, tin, antimony sulfosalt that forms in "cylinder" or "tube" shaped crystals, hence the name. In fact, this species belongs to the only group of minerals that naturally forms rounded, curved or tubular shaped crystals. The longest "cylinder" measures 15 mm. The mine at Poopo is the type locality for the species.