Proustite
Image: <a rel="nofollow" class="external text" href="http://www.mindat.org/user-14124.html#0">Terry Wallace</a> (Public domain)
Mineral NameProustite
Chemical FormulaAg3AsS3
Mohs Hardness2.5
Crystal Systemtrigonal
Lusteradamantine
Streak Colorscarlet red
Cleavagedistinct on {1011}
Fractureconchoidal
Specific Gravity5.57
Colorsruby-red, scarlet-red, cochineal-red
Transparencytransparent
Type LocalityChañarcillo, Copiapó Province, Atacama Region, Chile
Mineral Groupsulfosalts
Usesore of silver, collector
Associated Mineralsnative silver, argentite, galena, sphalerite, calcite, quartz
Rarityuncommon
Description
This image displays a stunning cluster of deep ruby-red proustite crystals, featuring prominent long prismatic forms with sharp terminations and excellent transparency.
Geological Context
Proustite typically forms in low-temperature hydrothermal veins, often associated with other silver minerals in the oxidation zone of silver deposits. It is a secondary mineral resulting from the alteration of primary silver ores.
