Jalpaite

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Jalpaite
Jalpaite-rom38a.jpg
Jalpaite crystals from Jalpa, Municipio de Jalpa, Zacatecas, Mexico (size: 3.6 x 3.5 x 3.2 cm)
General
CategorySulfide mineral
Formula
(repeating unit)
Ag3CuS2
Strunz classification2.BA.45
Crystal systemTetragonal
Crystal classDitetragonal dipyramidal (4/mmm)
H-M symbol: (4/m 2/m 2/m)
Space groupI41/amd
Unit cella = 8.67, c = 11.75 [Å]; Z = 8
Identification
ColorPale metallic gray
Crystal habitIrregular and foliated masses, inclusions in other minerals
CleavagePrismatic, good
FractureSubconchoidal
TenacitySectile, malleable
Mohs scale hardness2 - 2.5
LusterMetallic
StreakBlack
DiaphaneityOpaque
Specific gravity6.82–6.85
PleochroismDistinct in oil, brownish gray to pure gray
Alters toTarnishes with iridescence
References[1][2][3]

Jalpaite is a rare copper silver sulfide mineral with formula Ag3CuS2.

It was first described in 1858 for an occurrence in the Leonora Mine, Jalpa, Zacatecas, Mexico and named for the locality.[2] It occurs in low temperature hydrothermal veins at temperatures less than 117 °C (243 °F). Associated minerals include acanthite, mckinstryite, galena, sphalerite, pyrite, chalcopyrite, stromeyerite, polybasite, pearceite, tetrahedritetennantite and native silver.[1]

References[edit]