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.

Bismuthinite
Bismuthinite - Schlaggenwald (Horni Slavkov) - Bohemia - Czech Republic (XX 1.1cm)
General
Category	Sulfide mineral
Formula (repeating unit)	Bi2S3
Strunz classification	2.DB.05a
Crystal system	Orthorhombic
Crystal class	Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m)
Space group	Pbnm
Identification
Color	Lead-gray to tin-white, with a yellowish or iridescent tarnish.
Crystal habit	Slender prismatic to acicular, massive lamellar
Cleavage	[010] Perfect
Fracture	Uneven
Tenacity	Brittle, sectile
Mohs scale hardness	2
Luster	Metallic
Streak	Lead grey
Specific gravity	6.8 - 7.2
Optical properties	Opaque
References	[1][2][3]

Bismuthinite forms a series with the lead, copper, bismuth mineral aikinite (PbCuBiS₃).[3]

Bismuthinite crystal group from Bolivia (size: 2.9 x 1.9 x 1.5 cm)

This microprobe scan of a quartz-rich gold ore from the Ädelfors Goldmine shows the orientation of bismuthinite and various other phases, mostly maldonite, along trails, probably former cracks

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. Associated minerals include native bismuth, aikinite, arsenopyrite, stannite, galena, pyrite, chalcopyrite, tourmaline, wolframite, cassiterite and quartz.[1]

It was first reported in 1832 from the mines of Potosí, Bolivia.[2]