Jalpaite
Appearance
Jalpaite | |
---|---|
General | |
Category | Sulfide mineral |
Formula (repeating unit) | Ag3CuS2 |
Strunz classification | 2.BA.45 |
Crystal system | Tetragonal |
Crystal class | Ditetragonal dipyramidal (4/mmm) H-M symbol: (4/m 2/m 2/m) |
Space group | I41/amd |
Unit cell | a = 8.67, c = 11.75 [Å]; Z = 8 |
Identification | |
Color | Pale metallic gray |
Crystal habit | Irregular and foliated masses, inclusions in other minerals |
Cleavage | Prismatic, good |
Fracture | Subconchoidal |
Tenacity | Sectile, malleable |
Mohs scale hardness | 2 - 2.5 |
Luster | Metallic |
Streak | Black |
Diaphaneity | Opaque |
Specific gravity | 6.82–6.85 |
Pleochroism | Distinct in oil, brownish gray to pure gray |
Alters to | Tarnishes 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, tetrahedrite–tennantite and native silver.[1]