Cylindrite (very rare) (ex Dr. Vasco Trancoso Collection)

Item Description

Cylindrite is a very rare lead tin iron antimony sulfosalt species, which has the distinction of forming in uniquely cylindrical crystals. The morphology of the crystals is due to the fact that the crystals grow in two separate layers (one of which is pseudohexagonal, and the other is pseudotetragonal) , which grow nearly parallel to one another, but as they grow further from the center point of the crystal, they start to rotate and the unusual curvature of the crystal is formed. This piece is from Poopó, Bolivia where the finest examples of the species have been found over the years. The piece is loaded with dozens of excellent cylinder-shaped crystals of a dark silvery-grey hue measuring up to 2.7 cm on matrix. From the collection of Dr. Vasco Trancoso, a medical doctor and systematic mineral collector from Portugal (https://www.mindat.org/user-11954.html). This piece is pictured on mindat.org at https://www.mindat.org/photo-187836.html