This is the raw lead-gray bismuthinite specimen with feldspar. Dimensions: 2.8 x 1.8 x 1.1″ (7.1 x 4.6 x 2.9cm). Weight – 4.9oz (140 grams). Origin: Russia, Transbaikalia.
Some information about bismuthinite:
Bismuthinite is a mineral consisting of bismuth sulfide (Bi2S3). It is an important ore for bismuth. The crystals are steel-grey to off-white with a metallic luster. It is soft enough to be scratched with a fingernail and rather dense.
It occurs in hydrothermal veins with tourmaline-bearing copper veins associated with granite, in some high temperature gold veins, and in recent volcanic exhalation deposits.
It was first reported in 1832 from the mines of Potosí, Bolivia.