sphalerite


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sphalerite

(sfăl`ərīt, sfā`–), mineral composed of zinc sulfide, usually containing some iron and a little cadmium. It occurs in crystals of the isometric system but more generally in cleavable, compact masses. It is transparent to translucent and varies greatly in color, iron-free specimens being pale yellow and those with iron being brown, red, black, or green. The most important source of zinczinc,
metallic chemical element; symbol Zn; at. no. 30; at. wt. 65.38; m.p. 419.58°C;; b.p. 907°C;; sp. gr. 7.133 at 25°C;; valence +2. Zinc is a lustrous bluish-white metal. It is found in Group 12 of the periodic table.
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, sphalerite is a widely distributed mineral that commonly occurs in association with galena. It is found in large deposits in many parts of the world.

Sphalerite

 

(also blende), a mineral of the sulfide class with the chemical composition ZnS (67.1 percent Zn and 32.9 percent S). Sphalerite contains isomorphous admixtures of Fe (up to 26 percent), Mn, Cd, Ga, Ge, In, Co, and Hg. Varieties rich in Fe are known as marmatite, while the colorless and nearly colorless varieties are known as cleiophane. The structure of sphalerite is one of very dense cubic packing of S atoms with the tetrahedral interstices occupied by Zn atoms. The hexagonal modification of ZnS is called wurtzite. Certain sphalerites occur as banded inter-growths of cubic and hexagonal polytypic varieties.

Sphalerite occurs as granular masses, and the mineral frequently forms tetrahedral or dodecahedral crystals. In the absence of admixtures, it is colorless. The variations in color between brown and black are explained by the content of Fe. If Fe is present in small quantities, the greenish yellow color is caused by Cd, and the red color by Mn, Cu, and Ag and by In and Tl. Sphalerite has an adamantine luster, a hardness on Mohs’ scale of 3.5–1.0, and a density of 3,900–4,100 kg/m3, and it possesses piezoelectric and pyroelectric properties. It is formed in hydrothermal deposits together with galena, pyrite, chalcopyrite, arseno-pyrite, quartz, calcite, barite, and dolomite and in sedimentary deposits. In the zone of oxidation, sphalerite alters to zinc sulfate (goslarite) and smithsonite. Sphalerite is an important zinc ore.

A. S. MARFUNIN

sphalerite

[′sfal·ə‚rīt]
(mineralogy)
(Zn,Fe)S The low-temperature form and common polymorph of zinc sulfide; a usually brown or black mineral that crystallizes in the hextetrahedral class of the isometric system, occurs most commonly in coarse to fine, granular, cleanable masses, has resinous luster, hardness of 3.5 on Mohs scale, and specific gravity of 4.1. Also known as blende; false galena; jack; lead marcasite; mock lead; mock ore; pseudogalena; steel jack.
References in periodicals archive ?
(2) The first event of mineralization that presents quartz with massive texture, and coarse-grained pyrite with small inclusions of gold and is associated with galena, sphalerite, chalcopyrite and pyrrhotite.
Stage 2 hosts majority of the Pb-Zn mineralization in the Zhaxikang deposit and comprises an assemblage of MnFe carbonate + galena + sphalerite + pyrite [+ or -] arsenopyrite.
The percentage of surface liberation of chalcopyrite, galena, and sphalerite minerals was between 78 and 88% for particles containing 95-100% of the mineral of interest.
The ranges of Fe isotope compositions of chalcopyrite, pyrite, and sphalerite (Figure 2) are from -0.47[per thousand] to 0.35[per thousand], -2.14[per thousand] to -0.06[per thousand], and -1.08[per thousand] to -0.44[per thousand], respectively, with average [delta][sup.56]Fe values of -0.12 [+ or -] 0.24[per thousand] (n = 22), -1.18 [+ or -] 0.53[per thousand] (n = 48), and -0.82 [+ or -] 0.19[per thousand] (n = 22), respectively.
Keywords: low grade, lead-zinc ore, galena, sphalerite, beneficiation, froth flotation, grade, recovery
In 1991, the Zinc Corporation of America's mining operation to recover sphalerite from the stratabound Fowler orebody near Balmat in St.
The breccias contain abundant carbonate clasts and some sphalerite clasts.
SPHALERITE is mined in the northwestern Adirondack region for zinc ore.
The tailings materials contain remnant ore grains of galena, pyrite, sphalerite, and other minerals.
"Zinc metal is most commonly extracted from zinc sulphide mineral (sphalerite) concentrates that are produced at various mines by flotation," Leroux explains.
The deposit is contained within four closely-stacked lenses of massive sulphide mineralisation, characterised by chalcopyrite, sphalerite, banded pyrite, galena and minor tetrahedrite.