Cylindrite - San Francisco Mine, Poopo, Oruro, Bolivia

Cylindrite is a fascinating and uncommon tin-lead-antimony sulfosalt renowned for one of the most unusual crystal habits in the mineral kingdom. Its crystals form as extremely thin sheets that naturally curl and roll into tiny cylindrical tubes, giving the mineral its name and its distinctive appearance.
This specimen from the San Francisco Mine in Bolivia is richly covered with randomly oriented cylindrite crystals and tubes, producing an intricate metallic surface that is particularly rewarding under magnification. Its unusual crystal structure, strong metallic lustre and excellent coverage make this a fine representative example of a rare and highly distinctive mineral species.

Mineral: Cylindrite
Locality: San Francisco Mine, Poopó, Poopó Province, Oruro, Bolivia
Crystal System: Triclinic
Mineral Class: Sulfides (Sulfosalts)
Provenance: Ex Allan Ingelson Collection
Dimensions: 2.5 × 4 cm