Atacamite
Image: <bdi><a href="https://www.wikidata.org/wiki/Q56247090" class="extiw" title="d:Q56247090"><span title="mineral collector and dealer">Robert M. Lavinsky</span></a></bdi> (CC BY-SA 3.0)
Mineral NameAtacamite
Chemical FormulaCu2Cl(OH)3
Mohs Hardness3
Crystal Systemorthorhombic
Lusteradamantine
Streak Colorapple-green
Cleavagegood on {010}
Fractureconchoidal
Specific Gravity3.76
Colorsemerald-green, dark green, blackish-green
Transparencytransparent
Type LocalityLa Farola Mine, Cerro Pintado, Las Pintadas district, Tierra Amarilla, Copiapó Province, Chile
Mineral GroupHalides
Usescollector, minor ore of copper
Associated Mineralsmalachite, azurite, chrysocolla, cuprite, native copper
Rarityuncommon
Description
This specimen displays a matrix rock richly covered with a sparkling druse of dark emerald-green to blackish-green atacamite crystals, forming a vibrant, granular crust.
Geological Context
Atacamite is a secondary mineral found in the oxidized zone of copper deposits, particularly in arid regions where it forms from the alteration of primary copper sulfides in the presence of chloride-rich solutions.
