Covellite


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Related to Covellite: Enargite

covellite

[kō′ve‚līt]
(mineralogy)
CuS An indigo-blue mineral of metallic luster that crystallizes in the hexagonal system; it is usually massive or occurs in disseminations through other copper minerals and represents an ore of copper. Also known as indigo copper.

Covellite

 

(named for its discoverer, the Italian chemist N. Covelli, 1790–1829), a mineral of the sulfide class. Chemical composition, CuS; it contains 66.48 percent Cu and 33.52 percent S. The structure of covellite has Cu+ and Cu2+ atoms, as well as the simple ion S2– and the paired ion S22–. The structural elements of Cu2+ surrounded by three S2– and Cu+ ions, which are in the centers of paired tetrahedrons connected by S22 ions, are located in layers and provide the perfect cleavage of covellite. Thus, the structurally regular formula for covellite will be (Cu2S#x00B7;CuS2). Crystals are very rare; secondary incrustations, as well as films on other sulfides or powdery masses that replace them, are common. The color is dark blue. Hardness on the mineralogical scale, 1.5–2.0; density, 4,590–4,670 kg/m3. Covellite is a typical mineral in the zone of secondary sulfide enrichment in the oxidized parts of sulfide copper deposits. It is used as a copper ore.

References in periodicals archive ?
Secondary copper sulphide minerals such as bornite, chalcosite and covellite are the main culprits in this context, he explained, with Anglo Asian having included a SART (sulphidization-acidification-cyanide recycling-thickening) plant into its circuit to recover copper and silver from the pregnant solution as sulphides.
The mineral resource estimate shows that the hypogene mineral resource remains open to depth and along strike in most areas, and the higher grade supergene enriched mineralization, dominated by chalcocite and local covellite, is also open for expansion.
Transitional (underlying the above) - a variably developed, secondary, supergene pyrite (after pyrrhotite) -chalcocite - covellite - quartz dominant zone.
These shallow sub-economic occurrences contain manganese oxides, covellite, chalcopyrite, malachite, azurite, copper, and silver (Rose and Johnson 1990; Merlini 1998).
Primary copper mineralisation consists of chalcocite, bornite and chalcopyrite, with secondary mineralisation (chalcocite, chrysocolla, covellite, cuprite, azurite and wad) occurring along structures.
This last institution's case contained my candidate for most-downright-amazing specimen from Colorado: an extraordinary 20 X 20-cm mass of covellite crystals from Summitville, the sharp, hexagonal, dull blue-black crystals measuring uniformly about 2.
Examination of thin sections confirms the presence of widespread pentlandite together with millerite and lesser covellite.
The upper three blankets primarily contain oxide mineralization; below them is an intermediate horizon with secondary species mixed with primary sulfides; the two deepest blankets contain chiefly chalcocite and minor covellite.
There is a wide geologic variation present, from classic Cu/Au porphyry (sub-ore grade) to variable-thickness breccia pipes, higher-grade covellite with zones in pipes exceeding 100 m and grading >1% Cu.
Recognition of the presence of significant quantities of the enriched copper sulphides chalcocite and covellite allowed consideration of higher concentrate grades, particularly in early years.