Cylindrite Locality: Poopó town, Poopó Province , Oruro Department , Bolivia ( Locality at mindat.org ) A very rich specimen of lustrous, metallic, cylindrical crystals to 3.0 cm of the rare sulfosalt cylindrite from Poopo, Bolivia. These are very long crystals for the species and yes, they ARE truly weird cylndrical crystals!!!. Ex Richard Hauck Collection. HARD TO GET PIECES WITH SUCH NICE DEFINITION! 5.5 x 3.3 x 2.6 cm — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Cylindrite
A lead-tin-iron-antimony sulfosalt whose triclinic crystals roll into hollow tubes and cylinders — a unique habit in minerals.
Intro adapted from Wikipedia (CC BY-SA).
Cylindrite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula FePb₃Sn₄Sb₂S₁₄.
It crystallizes in the triclinic crystal system (space group A1). It is a member of the Cylindrite structural group.
Key properties: Mohs hardness 2.5; specific gravity 5.42–5.49; Black streak; Metallic luster.
IMA symbol Cy, grandfathered status — known before the IMA’s founding, named in 1893.
Found in tin-bearing hydrothermal veins.
It is found associated with Franckeite, stannite, incaite, potosiite, teallite, jamesonite, boulangerite, cassiterite, galena, pyrite, sphalerite.
In allusion to its typical cylindrical habit.