Brochantite

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Brochantite

General
Category Mineral
Chemical formula CuSO4·3Cu(OH)2
Identification
Color Green, emerald green, or black
Crystal habit Prismatic crystals; acicular needle-like crystals; also grows in a cavity which results in numerous crystal tipped surfaces
Crystal system Triclinic
Cleavage Perfect
Fracture Conchoidal
Mohs Scale hardness 3.5 - 4.0
Luster Vitreous
Pleochroism None
Streak Pale green
Specific gravity 3.9+

Brochantite is a sulfate mineral, one of a number of cupric sulfates. Its chemical formula is CuSO4·3Cu(OH)2. Formed in arid climates or in rapidly oxidizing copper sulfide deposits, it is named for its discoverer, the French geologist and mineralogist, A. J. M. Brochant de Villiers (1772-1840).

The mineral is found in a number of locations around the world, notably the southwestern United States (especially Arizona) and Chile.