Boulangerite

boulangerite

stibnite

arsenopyrite

sphalerite

Images

Formula: Pb5Sb4S11
Sulphosalt
Crystal System: Monoclinic
Specific gravity: 6.2 measured, 6.21 calculated
Hardness: 2½ to 3
Streak: Brown to brown-grey
Colour: Lead-grey
Common impurities: Cu,Zn,Sn,Fe
Environments:

Hydrothermal environments

Boulangerite occurs in low to moderate temperature hydrothermal veins (Webmin), associated with lead sulphosalts, galena, stibnite, sphalerite, pyrite, arsenopyrite, siderite and quartz (HOM)

Localities

The Bairendaba Ag-polymetallic deposit, Hexigten Banner, Chifeng City, Inner Mongolia, China, is a mesothermal magmatic-hydrothermal vein-type silver - lead - zinc deposit, hosted in Hercynian (about 419 to 299 million years ago) quartz diorite.
It is suggested that, with decreasing temperature, mineral compositions changed progressively from tungstate and oxide, to diatomic sulphide, to simple sulphide, to an antimony sulphosalt mineral, and finally to an antimonide.
Boulangerite occurs as free-growing acicular crystals and as inclusions associated with fluorite, quartz and calcite (Minrec 53.347-359).

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