Brochantite


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Related to Brochantite: cuprite

brochantite

[brō′shän‚tīt]
(mineralogy)
Cu4(SO4)(OH)6 A monoclinic copper mineral, emerald to dark green, commonly found with copper sulfide deposits; a minor copper ore. Also known as brochanite; brochanthite; warringtonite.

Brochantite

 

(named after the French 19th-century mineralogist A. J. M. Brochant de Villiers), a mineral of the class of sulfates. It has an insular-type structure made up of PO4 tetrahedrons connected by Cu arranged in the center of the octahedron Cu[(OH)5O]. Its chemical composition is Cu4[SO4](OH)6. Brochantite crystallizes in a monoclinic system. It is found in the form of crystalline crusts with druses of small, needle-like dark-green crystals or in the form of powdery masses. The mineral’s hardness on the mineralogic scale measures 3.5-4.0; its density is 3,800-4,100 kg/m3. Brochantite is formed in the zones of oxidation of deposits of copper sulfide ores under the conditions of a hot, dry climate. Along with other minerals of the zones of oxidation of copper deposits, such as atacamite, chrysocolla, and azurite, it may serve as a copper ore.

References in periodicals archive ?
Reaction pathway and kinetics of the thermal decomposition of synthetic brochantite, Journal of thermal analysis, 49: 1467-1475.
4] and Cl in these waters suggest that brochantite is currently being replaced by atacamite (Cameron et al.
Researchers blamed antlerite's presence on acidic rain, dew, fog and particulates, which made the statute's surface too acidic for brochantite to remain stable, says Robert Baboian, a corrosion scientist at Texas Instruments, Inc.
It consists mainly of brochantite and a basic copper chloride called atacamite, CuCl.
Copper minerals comprising the "oxide zone" include chrysocolla, atacamite, conicalcite, malachite and azurite, with lesser brochantite, calcantite (green and blue copper), cuprite, copper-bearing hematite (red copper) and tenorite, neotocite and copperwad (black copper) with the occurrence of more rare copper minerals.
Baboian's results suggest that acid rain may be converting a stable form of basic copper sulfate called brochantite, CuSO4 3Cu(OH)2, which formed naturally on the statue's copper surface, into a less stable form of copper sulfate called antlerite, CuSO4 2Cu(OH)2.
Samples from this initial exposure are characterized by Brochantite, and have returned high grade copper analyses to 46.