Brochantite (Cu₄(SO₄)(OH)₆) is a hydrous copper sulfate forming in the oxidized cap zones of copper deposits as emerald-green tabular and acicular crystals. Tsumeb (Namibia) and Milpillas (Mexico) supply collector-grade specimens with vivid green color on chalcocite and chrysocolla matrix.
Key Facts
- Mohs hardness 3.5–4.
- Monoclinic; tabular and acicular crystal habits.
- Emerald to deep green color from Cu²⁺.
- Common in oxidized Cu cap zones with malachite, azurite, chrysocolla.
- Toxic — soluble copper sulfate component.
Notable Localities
Tsumeb (Namibia), Milpillas (Sonora, Mexico), and Chuquicamata (Chile) yield collector specimens.
Found at these Localities
- Chuquicamata (丘基卡马塔铜矿)
- Tsumeb Mine (楚梅布矿)
