Brochantite

Infobox mineral
name = Brochantite
category = Sulfate mineral
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caption =
formula = Cu₄SO₄(OH)₆
molweight =
color = Green, emerald green, or black
habit = Prismatic crystals; acicular needle-like crystals; druse
system = Monoclinic
twinning =
cleavage = Perfect [100]
fracture = Conchoidal - brittle
mohs = 3.5 - 4.0
luster = Vitreous - pearly
refractive = nα = 1.728 nβ = 1.771 nγ = 1.800
opticalprop = Biaxial (-), 2V measured: 72°
birefringence = δ = 0.072
pleochroism = Weak
streak = Pale green
gravity = 3.97
melt =
fusibility =
diagnostic =
solubility =
diaphaneity = Transparent to translucent
other =
references = [http://webmineral.com/data/Brochantite.shtml Webmineral] [http://rruff.geo.arizona.edu/doclib/hom/brochantite.pdf Mineral Handbook] [http://www.mindat.org/min-779.html Mindat]

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.

References