Enargite


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enargite

[e′när‚jīt]
(mineralogy)
A lustrous, grayish-black mineral which is found in orthorhombic crystals but is more commonly columnar, bladed, or massive; hardness is 3 on Mohs scale, specific gravity is 4.44; in some places enargite is a valuable copper ore. Also known as clairite; luzonite.

Enargite

 

a mineral of the sulfide class, with chemical composition Cu3 AsS4. Enargite, which contains admixtures of Sb (up to 6 percent), Fe, or Zn, crystallizes in the orthorhombic system, forming steel gray or greenish black tabular or prismatic crystals. Twins are common, while stellated trillings occur less often. The mineral is also found in the form of granular aggregates. Enargite is opaque, with a metallic luster and perfect cleavage in one direction. It has a hardness of 3.5 on Mohs’ scale and a density of 4,300–4,500 kg/m3.

Enargite occurs in hydrothermal average-temperature deposits, such as copper-pyrite, copper-porphyry, and pyrite-enargite deposits. Upon the weathering of enargite, malachite, azurite, copper arsenates, and other minerals form. Enargite, together with other minerals in copper deposits, is a constituent of certain copper ores.

References in periodicals archive ?
They suggested that the sulfide saturation of pyrite and enargite ([Cu.sub.3] As[S.sub.4]) occurred directly in acidic waters (pH = 0.4) and was induced by upward-streaming [H.sub.2]S-bearing gases.
The mineral resource is largely contained in a secondary chalcocite enrichment zone and local enargite, forming a sub-horizontal mineralized body with horizontal dimensions of 500 by 1,000 m and thickness of 50 to 200 m.
The oxidative dissolution of arsenopyrite (FeAsS) y enargite (Cu3AsS4) by Leptospirillum ferrooxidans.
The possibilities of using flotation techniques to beneficiate gold-bearing ores containing enargite concentrates for pyrometallurgical treatment are being investigated at Sardinian Gold Mining's Furtei operation in southern Sardinia.
There is easily minable classic, sub-horizontal supergene material below the oxides in mixed covellite and enargite (not in the porphyry).
The majority of the mineralisation encountered in the hole is enargite. The mineralised body has now been delineated over a 1.6 km strike length, a width of 200-600 m, and to a depth of at least 150 m.
Today the Butte mines are closed and flooded, but its mineralogical legacy of fine specimens remains--most noteably the copper sulfide and sulfosalt minerals such as bornite, chalcocite, chalcopyrite, colusite, covellite, digenite, djurleite, and enargite, and other minerals such as barite, pyrite, quartz and silver.
This makes the process particularly competitive for treating minerals such as enargite, a copper-arsenic sulphide.
The southeast/northwest striking veins contain mainly quartz, massive pyrite, and enargite with chalcocite in the secondary enrichment zone.