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.jpg
Bismuthinite - Schlaggenwald (Horni Slavkov) - Bohemia - Czech Republic (XX 1.1cm)
General
CategorySulfide mineral
Formula
(repeating unit)
Bi2S3
Strunz classification2.DB.05a
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPbnm
Identification
ColorLead-gray to tin-white, with a yellowish or iridescent tarnish.
Crystal habitSlender prismatic to acicular, massive lamellar
Cleavage[010] Perfect
FractureUneven
TenacityBrittle, sectile
Mohs scale hardness2
LusterMetallic
StreakLead grey
Specific gravity6.8 - 7.2
Optical propertiesOpaque
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]

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