Stibnite

stibnite

cinnabar

antimony

galena

Images

Formula: Sb2S3
Sulphide, stibnite group, antimony-bearing mineral
Crystal System: Orthorhombic
Specific gravity: 4.63 measured, 4.625 calculated
Hardness: 2
Streak: Dark grey
Colour: Lead-grey
Solubility: Moderately soluble in hydrochloric acid; slightly soluble in nitric acid
Melting point: 546oC
Environments:

Hot spring deposits
Hydrothermal environments common

Stibnite is found in epithermal (low temperature) hydrothermal veins, particularly in stibnite- quartz veins, in replacement deposits and in hot spring deposits. It is associated with other antimony minerals that have formed as the product of its decomposition, and with galena, cinnabar, sphalerite, baryte, realgar, orpiment and gold.

Localities

At the Xikuangshan Sb deposit, Lengshuijiang County, Loudi, Hunan, China, stibnite occurs as lustrous, metallic crystals, sometimes as large aggregates (AESS).
Stibnite from Xikuangshan - Image

At the Wuning Mine, Qingjiang, Wuning county, Jiujiang, Jiangxi, China, some of the largest and finest specimens of stibnite have been recovered from the "Cave of Giants" (MinRec 55.3.274-277).
Stibnite from Wuning - Image

At Schemnitz, Slovakia, stibnite occurs with stibiconite (FM OP33).

At Wet Swine Gill, Coombe Height, Caldbeck, Allerdale, Cumbria, England, UK, stibnite occurs as tiny glittery silver specks on a quartz matrix, with specks of a yellow mineral that is possibly orpiment (AESS).

Stibnite from Wet Swine Gill - Image

Alteration

chalcopyrite, stibnite and sulphur to Fe-tetrahedrite and pyrite
10 CuFeS2 + 2 Sb2S3 + 3/2 S2 → Cu10Fe2As4S13 + 8FeS2
(CM 28.725-738)

stibnite and pyrite to berthierite and sulphur
Sb2S3 + FeS2 → FeSb2S4 + l/2S2
(CM 28.725-738)

Fe-tetrahedrite, berthierite and sulphur to chalcopyrite and stibnite
Cu10Fe2Sb4S13 + 2FeSb2S4 + 11/2S2 → 10CuFeS2 + 4Sb2S3
(CM 28.725-738)

Fe-tetrahedrite, siderite and sulphur to chalcopyrite, stibnite, CO2 and O2
Cu10Fe2Sb4S13 + 8Fe(CO3) + 13/2S2 → 10CuFeS2 + 2Sb2S3 + 8CO2 + 4O2
(CM 28.725-738)

Zn-tetrahedrite to skinnerite, stibnite and sphalerite
3Cu10Zn2Sb4S13 → 10Cu3SbS3 + Sb2S3 +6ZnS
(CM 28.725-738)

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