This is the ONLY species of natural crystal with a cylindrical crystal habit! Cylindrite is an uncommon lead tin iron antimony sulfide (sulfosalt). What makes it really amazing is that it is the only naturally occurring mineral species with cylindrical crystals! This specimen is from the type locality at Poopo, Bolivia. Massive dark gray ore hosts splendent, diverging, dark gray crystals of cylindrite, to nearly 3cm in length. Crystals are growing at a steep angle relative to the bounding ore margins. These "cylinders" are of quite good size for the species and it is a very rich piece overall. Although many have come out, this one is extremely good and is a great display specimen.