Brochantite

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Brochantite
Brochantite.jpg
General
Category Sulfate minerals
Formula
(repeating unit)
Cu4SO4(OH)6
Strunz classification 07.BB.25
Identification
Color Green, emerald green, or black
Crystal habit Prismatic crystals; acicular needle-like crystals; druse
Crystal system Monoclinic
Cleavage Perfect [100]
Fracture Conchoidal - brittle
Mohs scale hardness 3.5 - 4.0
Luster Vitreous - pearly
Streak Pale green
Diaphaneity Transparent to translucent
Specific gravity 3.97
Optical properties Biaxial (-), 2V measured: 72°
Refractive index nα = 1.728 nβ = 1.771 nγ = 1.800
Birefringence δ = 0.072
Pleochroism Weak
References [1]<[2]<[3]

Brochantite is a sulfate mineral, one of a number of cupric sulfates. Its chemical formula is Cu4SO4(OH)6.[1][2][3] 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.[1]

Crystals of brochantite can range from emerald green to black-green to blue-green, and can be acicular or prismatic. Brochantite is often associated with minerals such as malachite, azurite, and chrysocolla, and may form pseudomorphs with these minerals.

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

References[edit]

External links[edit]