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Semseyite

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Semseyite
Semseyite - Brioude-Massiac (Massif Central) France (11x3.5cm)[1]
General
CategorySulfosalt mineral
Formula
(repeating unit)
Pb9 Sb 8 S21
IMA symbolSsy[2]
Strunz classification2.HC.10d
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupC2/c
Unit cella = 13.64 Å, b = 11.96 Å
c = 24.46 Å; β = 105.87°; Z = 4
Identification
ColorDark gray to black
Crystal habitTabular, elongated prismatic crystals, commonly twisted; rosettelike groups
CleavagePerfect on {112}
TenacityBrittle
Mohs scale hardness2.5
LusterMetallic
Diaphaneityopaque
Specific gravity6.15
References[3][4][5]

Semseyite is a rarely occurring sulfosalt mineral and is part of the class of lead antimony sulfides. It crystallizes in the monoclinic system with the chemical composition Pb9Sb8S21. The mineral forms dark gray to black aggregates.

Etymology and history

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Semseyite was first described for an occurrence in the Felsöbánya mine in Baia Sprie, Romania in 1881 by József Sándor Krenner (1839–1920). The mineral was named after Hungarian mineralogist Andor von Semsey (1833–1923).

Occurrence

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Semseyite forms in hydrothermal solutions at temperatures between 300 and 350 °C.[6] It occurs in association with bournonite, jamesonite, sphalerite, zinkenite, sorbyite, guettardite, jordanite, diaphorite, galena, pyrite, chalcopyrite, tetrahedrite, arsenopyrite and siderite.[3]

Images

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References

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  1. ^ J.J. Périchaud : "Metal Layers of the District with Antimony of Brioude-Massiac (French Massif Central)", BRGM, 1968
  2. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  3. ^ a b Handbook of Mineralogy
  4. ^ Mindat
  5. ^ Webmineral data
  6. ^ Andreas Kamrath: “Geology and mineralogy of ore stores Herja” Archived 2011-02-13 at the Wayback Machine