Kermesite

kermesite

stibiconite

valentinite

senarmontite

Images

Formula: Sb2OS2
Sulphide
Crystal System: Triclinic
Specific gravity: 4.5 to 4.6 measured, 4.85 calculated
Hardness: 1 to 1½
Streak: Brownish red
Colour: Red
Environments:

Metamorphic environments
Hydrothermal environments

Kermesite is a secondary mineral that forms as an alteration of stibnite, in antimony deposits (Webmin). The oxidation often continues changing kermesite to senarmontite (AES). Associated minerals include stibnite, antimony, senarmontite, valentinite, cervantite and stibiconite (HOM).

Localities

At the Lac Nicolet Antimony mine, Saints-Martyrs-Canadiens, Arthabaska RCM, Centre-du-Québec, Quebec, Canada, fine specimens of kermesite have been found with crimson-red to maroon crystals to 5 cm, associated with valentinite, native antimony, quartz and stibnite. The mineralisation is hosted in greenschist facies slate, quartzite, phyllite and serpentinite. Hydrothermal fluids invaded the country rocks and produced the antimony-bearing quartz veins containing the various mineral assemblages (R&M 94.5.444-445).
Kermesite from the Lac Nicolet Antimony Mine _ Image

At the Damingshan Mountain, Shanglin county, Guangxi, China, exceptional kermesite crystals were found in a single pocket, associated with stibnite, valentinite, senarmontite and very rarely pääkkönenite (Minrec 38.1.16).
Kermesite from Shanglin County - Image

At the Zhenwei (Zhenxu) antimony-gold deposit, Shanglin county, Guangxi, China, kermesite occurs in the upper oxidation zone, together with cervantite (Minrec 38.1.15-16).

At the type locality, the Neue Hoffnung Gottes Mine, Bräunsdorf, Niederwiesa, Mittelsachsen, Saxony, Germany, kermesite occurs in quartz vein vugs as sprays of small, lustrous red crystals associated with stibnite, berthierite and valentinite (R&M 94.5.442)
Kermesite from the Neue Hoffnung Gottes Mine - Image

At the Krížnica Deposit, Pernek, Malacky District, Bratislava Region, Slovakia, antimony mineralisation is associated with shale and phyllite. There were three stages of ore formation, first quartz - pyrite - arsenopyrite, then stibnite - carbonate - quartz, and finally stibnite - kermesite. The kermesite forms dark red radial aggregates to 6 cm together with stibnite, valentinite, senarmontite, schafarzikite and late-stage aragonite and calcite (R&M 94.5.444)
Kermesite from the Krížnica Deposit - Image

At the Kolársky vrch deposit, Pezinok, Pezinok District, Bratislava Region, Slovakia, kermesite forms excellent radial aggregates of acicular crystals, rarely up to 14 cm, associated with stibnite, valentinite, calcite, and siderite (R&M 94.5.444)
Kermesite from the Kolársky Vrch Deposit - Image

Herichová, Chyžné, Revúca District, Banská Bystrica Region, Slovakia, the first occurrence of kermesite associated with valentinite and jamesonite was found on the stockpile of the old tunnels. Other associated secondary minerals include anglesite, cerussite, gypsum, senarmontite, scorodite and stibiconite. The radial aggregates of kermesite are less than 1 cm across, bright red, and found in quartz vugs to 5 cm across (R&M 94.5.444)
Kermesite from Herichová - Image

At the Globe and Phoenix mine, Kwekwe, Kwekwe District, Midlands, Zimbabwe, kermesite mineralisation was hosted in quartz veins in talc - carbonate schist and tonalitic gneiss, associated with extensive alteration accompanied by muscovite varieties sericite and fuchsite. The veins occur at the contact between the Kwekwe ultramafic complex and granite gneiss. This mine has produced some of the finest kermesite specimens known outside China (R&M 94.5.440-446).
Kermesite from the Globe and Phoenix Mine - Image

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