arsenopyrite


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Related to arsenopyrite: pyrrhotite, molybdenite

arsenopyrite

(är'sĭnōpī`rīt, ärsĕn`ō–) or

mispickel

(mĭs`pĭkəl), silver-white to steel-gray mineral with the metallic luster characteristic of a pyritepyrite
or iron pyrites
, pale brass-yellow mineral, the bisulfide of iron, FeS2. It occurs most commonly in crystals (belonging to the isometric system and usually in the form of cubes and pyritohedrons) but is also found in massive, granular, and stalactite
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. It is a sulfarsenide of iron, FeAsS, crystallizing in the orthorhombic system and occurring also in massive form. It is widely distributed and is an important source of arsenic. Often it is found associated with other minerals and ores of lead and tin. Saxony, Sweden, Cornwall, and various parts of the United States have important deposits.

Arsenopyrite

 

(or mispickel), a mineral belonging to the group of the sulfur-arsenic compounds of iron. The chemical composition is FeAsS. It usually contains admixtures of an isomorphic nature (cobalt, nickel). It forms the series arsenopyrite (up to 3 percent Co)-danaite (up to 12 percent Co)-glaucodot (more than 12 percent Co). The system is mono-clinic (by the latest data, triclinic); it forms pseudorhombic, prismatic, columnar, and needlelike crystals, starlike growths, and columnar and grainy aggregates. Arsenopyrite has a metallic luster, and its color is tin-white. Its hardness on the mineralogical scale is 5.5–6. The density is 5,9000–6,200 kg/m3. When struck, arsenopyrite gives off a sharp odor of garlic. Arsenopyrite is encountered in ore veins together with the sulfides of lead, zinc, and bismuth, as well as with tungsten, cassiterite, gold nuggets, and others. Formation within a wide temperature range is characteristic of arsenopyrite. (It is found in pegmatites and hydrothermal deposits.) Upon being subjected to weathering and oxidation of the surface of the earth, arsenopyrite is transformed into scorodite and other hydrated arsenates of iron. Arsenopyrite is the principal raw material for the extraction of arsenic, and less frequently of cobalt and nickel.

arsenopyrite

[‚ärs·ən·ō′pī‚rīt]
(mineralogy)
FeAsS A white to steel-gray mineral crystallizing in the monoclinic system with pseudo-orthorhombic symmetry because of twinning; occurs in crystalline rock and is the principal ore of arsenic. Also known as mispickel.
References in periodicals archive ?
As is mainly linked to Fe oxides because once weathering, a process typical of C horizons, releases As from As-bearing primary minerals (mainly arsenopyrite), it shows a great affinity for Fe oxides, to which it is bound by adsorption and coprecipitation [56].
Mineral volume fraction of each primary mineral was chosen from a similar quantity of Navajo Sandstone with the addition of 1% arsenopyrite; quartz was predominant (81%), and kaolinite accounted for the second-largest amount (16%).
These are characterized by disseminated scheelite, arsenopyrite and pyrite.
Mineralization in hole TOG-13-25 is described as strongly albitized and silicified conglomerate and porphyry units containing 1 to 8 percent finely disseminated pyrite with local arsenopyrite. Visible gold was noted in 9 different locations within this intercept.
Megascopic and microscopic examination of ore samples collected at two prospecting pits and the inferred principal pre-Hispanic working indicates the presence of high-grade malachite, [Cu.sub.2]C[O.sub.3] [(OH).sub.2] as well as a variety of weathered but high-grade (up to 25% concentration) copper sulfides, particularly chalcopyrite, CuFeS2, and to a lesser extent, bornite, [Cu.sub.5]Fe[S.sub.4], and arsenopyrite, FeAsS.
Chemical and biological pathways in the bacterial oxidation of arsenopyrite. FEMS Microbiol Rev.
Physicochemical properties of soil that were significant predictors (p < 0.10) of As RBA estimates were also significant predictors of IVBA estimates, with the exception of percent arsenopyrite. Among predictors, sums of concentrations of extractable soil Fe and Al (Fe + Al) accounted for the largest amount of variation in RBA and IVBA escimates ([R.sup.2] = 0.58 and 0.40, respectively).
Cobaltite typically occurred in the Blackbird mine as microscopic, reddish gray grains in quartz with tourmaline and cobalt-rich arsenopyrite. Cubic and octahedral crystals of cobaltite to 5 mm were also found disseminated in quartz, associated with biotite, chlorite and apatite (Ream, 2004).
Gold occurs with disseminated arsenopyrite and chalcopyrite within the intrusive rocks, and in quartz stockworks and sheeted quartz veins.
During the roasting of arsenopyrite concentrates for their gold recovery, flue dust containing 60-70% arsenic trioxide is collected through the gas handling system.