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Brochantite always occurs in a striking deep green color. It is almost exclusively in groups of small radiating needles, and almost always found together with the very similar mineral Cyanotrichite, which has a deep blue color. The combination of bright green Brochantite and bright blue Cyanotrichite creates a beautiful and contrasting specimen.
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Chemical Formula |
CuSO4(OH)6 |
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Composition |
Basic copper sulfate |
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Color |
Bright green to dark green |
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Streak |
Pale green |
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Hardness |
3.5 - 4 |
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Crystal System |
Monoclinic |
Crystal Forms
and Aggregates |
Very rarely in visible crystals, which are prismatic and tabular. Most often acicular, radiating, earthy, grainy, encrusting, as fibrous masses, as dense bundles of acicular crystals, and as cotton-like, radiating masses. Sometimes occurs as tiny twinned crystals that appear orthorhombic with rounded corners.
Brochantite occasionally forms a pseudomorph after Azurite and Malachite and can assume the crystal shape of those minerals.
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Transparency |
Transparent to opaque |
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Specific Gravity |
4 |
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Luster |
Vitreous to silky |
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Cleavage |
1,1 - pinacoidal |
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Fracture |
Conchoidal, uneven, splintery |
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Tenacity |
Brittle |
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In Group |
Sulfates; Hydrous Sulfates |
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Striking Features |
Intense green color, crystal habits, and mode of occurrence |
| Environment |
Brochantite is a secondary copper mineral formed in the oxidation zone of copper deposits. |
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Popularity (1-4)
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3 |
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Prevalence (1-3)
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2 |
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Demand (1-3) |
2 |
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Brochantite is a minor ore of copper.
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Fine African localities are Katanga (Shaba), Congo (Zaire); Tsumeb, Namibia; and Goulmina, Mujuram, and Touissit, Morocco. Other Worldwide occurences are Cloncurry, Mt Isa, Queensland, Australia; the Chengmenshan Mine, Jiurui, Jiangxi Province, China; and Copiapo and Chuquicamata, in the Atacama Desert, Chile. In Mexico, Brochantite comes from the Ojuela Mine, Mapimi, Durango; and a new limited find of some of the finest examples of this mineral was discovered in the Milpillas Mine, Sonora.
Excellent specimens have also come from many areas in the southwestern U.S. Arizona localities are Bisbee, Cochise Co.; Clifton and Morenci, Greenlee Co.; and the Grandview Mine, Concino Co. Other Southwest occurrences are Bingham, Socorro Co., New Mexico; the Douglas Hill Mine, Artesia Lake, Lyon Co., Nevada; the Tintic District, Juab Co., Utah; and the Green Monster mine, Independence, and Cerro Gordo, Inyo Co., California.
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Malachite - Effervesces in hydrochloric acid; otherwise practically indistinguishable from Brochantite.
Antlerite - Virtually indistinguishable from Brochantite without complex tests.
Dioptase - Crystals are not elongated like Brochantite.
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