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
Cleavageperfect 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, Atacama Region, Chile
Mineral GroupHalides
Usescollector, minor copper ore
Associated Mineralscuprite, malachite, chrysocolla, brochantite
Rarityuncommon
Description
This specimen features dark green to emerald-green atacamite crystals, often forming radiating or acicular aggregates, embedded within a lighter green matrix.
Geological Context
Atacamite is a secondary copper mineral that forms in the oxidized zone of copper deposits, particularly in arid climates. It results from the alteration of primary copper sulfides in the presence of chloride-rich solutions.
