Formula: Cu3SbS3
Sulphosalt, antimony-bearing mineral
Crystal System: Monoclinic
Specific gravity: 5.11 calculated
Hardness: 3
Streak: Grey-black
Colour: Grey
Common impurities: Ag

Plutonic igneous environments


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.


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)

Back to Minerals