Cylindrite

Locality: Trinacria Mine, Callipampa, Poopó Province, Oruro Department, Bolivia Dimensions: 2.9 cm x 2 cm x 1.2 cm “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”

Chemical Formula: Pb3Sn4FeSb2S14
Locality: Poopo, in Oruro, Boliva.
Name Origin: From the Greek, kylindros, “cylinder.”

Cylindrite is a sulfosalt mineral containing tin, lead, antimony and iron with formula: Pb3Sn4FeSb2S14. It forms triclinic pinacoidal crystals which often occur as tubes or cylinders which are in fact rolled sheets. It has a black to lead grey metallic colour with a Mohs hardness of 2 to 3 and a specific gravity of 5.4.

It was first discovered in the Santa Cruz mine, Oruro Department, Bolivia in 1893. The name arises from its curious cylindrical crystal which it forms almost uniquely among minerals.

Physical Properties of Cylindrite

Cleavage: None
Color: Lead gray, Grayish black.
Density: 5.4 – 5.42, Average = 5.41
Diaphaneity: Opaque
Fracture: Malleable – Deforms rather than breaking apart with a hammer.
Hardness: 2.5 – Finger Nail
Luster: Metallic
Streak: black

Photos :

Cylindrite Santa Cruz mine, Poopó, Bolivia Specimen weight:93 gr. Crystal size:18 mm Overall size: 48mm x 35 mm x 35 mm Copyright © minservice
Cylindrite 2.4×2.0x1.4 cm Santa Cruz Mine, Poopo, Oruro, Bolivia Copyright © 2011 David K. Joyce Minerals
Cylindrite 7.0×5.7×5.4 cm Santa Cruz Mine, Poopo, Oruro, Bolivia Copyright © 2011 David K. Joyce Minerals
Santa Cruz Mine, Poopó town, Poopó Province, Oruro Department, Bolivia