Atacamite (Cu₂Cl(OH)₃) is a copper chloride hydroxide forming in the oxidized cap zones of copper deposits in arid environments. Named after the Atacama Desert (Chile) where it is abundant, Atacamite produces vivid emerald-green prismatic crystals on cuprite or limonite matrix. Modern collector specimens come from Chile, Australia, and Tsumeb (Namibia).
Key Facts
- Mohs hardness 3–3.5.
- Orthorhombic; prismatic to tabular crystals.
- Vivid emerald-green color is diagnostic.
- Stable only in arid climates — readily alters to malachite/paratacamite in humid environments.
- Common in Atacama (Chile) Cu oxide caps.
Notable Localities
Atacama Desert (Chile), Burra Burra (Australia), and Tsumeb (Namibia) yield collector specimens.
Found at these Localities
- Chuquicamata (丘基卡马塔铜矿)
- Boleo District (Santa Rosalía) (圣罗萨利亚博莱奥铜矿区)
- Tsumeb Mine (楚梅布矿)
