Murdochite, Brochantite, Calcite Dimensions: 65 mm × 50 mm × 38 mm Locality: Sunshine No. 6 adit, Blanchard Mine, Bingham, Hansonburg District, Socorro County, — Photo: John Sobolewski (JSS) · CC BY 3.0
Brochantite
A green copper sulfate formed in arid climates and rapidly oxidizing copper deposits, named for French mineralogist A. J. M. Brochant de Villiers.
Intro adapted from Wikipedia (CC BY-SA).
Brochantite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Cu₄(SO₄)(OH)₆.
It crystallizes in the monoclinic crystal system (space group P2_1/a). It is a member of the Brochantite structural group.
Key properties: Mohs hardness 3.5–4; specific gravity 3.97; typically green; Pale green streak; Vitreous, somewhat pearly on cleavages luster; refractive index 1.766; optically biaxial.
IMA symbol Bct, IMA status: approved, named in 1824.
Common in the oxidized zone of copper deposits, yet rarely an ore; formed under low acidity, principally in arid regions.
It is found associated with Malachite, azurite, tenorite, cuprite, linarite, caledonite, cerussite, atacamite, chrysocolla, cyanotrichite, iron oxides.
The mineral was named to honor Professor André Jean François Marie Brochant de Villiers (1772–1840), French geologist and mineralogist, School of Mines, Paris, France.
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