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Formula: Cu3SbS3
Sulphosalt, antimony-bearing mineral
Crystal System: Monoclinic
Specific gravity: 5.11 calculated
Hardness: 3
Streak: Grey-black
Colour: Grey
Common impurities: Ag
Environments
Localities
At the type locality, the skinnerite occurrence at Kangerluarsuk Fjord, Ilímaussaq complex, Narsaq, Kujalleq,
Greenland,
skinnerite occurs intergrown with senarmontite,
valentinite, native antimony,
tetrahedrite,
chalcostibite,
galena and traces of löllingite.
These minerals
form ore aggregates less than 1 cm in size disseminated in
analcime-natrolite veins cutting
naujaite. Indications are that the ore aggregates crystallised at
about 400oC
from metal-rich residual magmatic fluids deficient in sulphur.
Minerals contained in similar veins in surrounding bedrock outcrops include
natrolite,
analcime, ussingite,
sodalite, feldspar,
aegirine and arfvedsonite. The
silicate minerals
of the boulders containing the skinnerite consist of about 90%
analcime containing
natrolite and minor amounts of
albite,
aegirine, arfvedsonite and
altered
steenstrupine-(Ce)
(AM 59.889-895, HOM).
Bankov magnesite deposit, Košice I, Košice, Košice Region, Slovakia, is the source of fine, but small, crystals of
skinnerite. See photos on Mindat.
Alteration
chalcostibite and chalcocite to
skinnerite
CuSbS2 + Cu2S → Cu3SbS3
(CM 28.725-738)
skinnerite to chalcocite,
antimony and sulphur
2Cu3SbS3 → 3Cu2S + 2Sb + 3/2S2
(CM 28.725-738)
skinnerite and sphalerite =
Zn-tetrahedrite and chalcocite
4Cu3SbS3 + 2ZnS → Cu10Zn2Sb4S13 + Cu2S
(CM 28.725-738)
Zn-tetrahedrite to skinnerite,
antimony, sphalerite and
sulphur
3Cu10Zn2Sb4S13 → 10Cu3SbS3 + 2Sb + 6ZnS + 3/2S2
(CM 28.725-738)
Zn-tetrahedrite to skinnerite,
stibnite and sphalerite
3Cu10Zn2Sb4S13 → 10Cu3SbS3 + Sb2S3 +6ZnS
(CM 28.725-738)
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