Andorite

Andorite

Andorite - Itos Mine, Oruro City, Cercado Province, Bolivia. Specimen height is 4.1 cm.
General
Category Sulfosalt mineral
Chemical formula PbAgSb3S6
Strunz classification 02.JB.40a
Crystal symmetry Orthorhombic (2/m 2/m 2/m) dipyramidal
Unit cell a = 12.99 Å, b = 19.14 Å, c = 4.3 Å; Z = 4
Identification
Color Dark steel-gray, may tarnish yellow or iridescent; white in polished section
Crystal habit Crystals stout prismatic to tabular on {100}, striations parallel to [001]; massive
Crystal system orthorhombic
Twinning On {110}
Cleavage none observed
Fracture conchoidal
Mohs scale hardness 3 - 3.5
Luster metallic
Streak Black
Diaphaneity Opaque
Specific gravity 5.33 - 5.37
Optical properties anisotropic
References [1][2]

Andorite is a sulfosalt mineral with the chemical formula PbAgSb3S6.

It was first described in 1892 for an occurrence in the Baia Sprie mine, Baia Sprie, Maramures County, Romania, and named for Hungarian amateur mineralogist Andor von Semsey (1833-1923).[1] [3] Andorite occurs in low-temperature polymetallic hydrothermal veins. It occurs associated with stibnite, sphalerite, baryte, fluorite, siderite, cassiterite, arsenopyrite, stannite, zinkenite, tetrahedrite, pyrite, alunite, quartz, pyrargyrite, stephanite and rhodochrosite.[2]

References