Scorodite


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scorodite

[′skȯr·ə‚dīt]
(mineralogy)
FeAsO4·2H2O A pale leek-green or liver-brown orthorhombic mineral consisting of ferric arsenate; isomorphous with mansfieldite and represents a minor ore of arsenic.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Scorodite

 

a mineral with the chemical composition Fe[AsO4].2H2O. Scorodite contains 34.60 percent Fe2O3, 49.79 percent As2O5, and 15.61 percent H2O; if it contains more than 16 percent P2O5, it is called phosphoscorodite. Scorodite crystallizes in the orthorhombic system, forming dipyramidal, tabular, or prismatic crystals. Solid earthy aggregates, incrustations, spherulites, and microcrystalline druses are common. Scorodite is pale green, grayish green, or grayish brown in color. It has a hardness of 3.5—4 on the Mohs’ scale, and its density ranges from 3,100 to 3,300 kg/m3.

Scorodite is a mineral from the oxidation zone of deposits containing arsenical pyrites (for example, arsenopyrite) or loellingite. Together with these minerals, it serves as raw material for the extraction of arsenic. In the USSR, scorodite deposits are found in Kazakhstan, Uzbekistan, Transbaikalia, and the Urals; it is also found in the German Democratic Republic (Saxony), the USA, and Brazil.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Additionally, there was one well resolved band, peaked at 825-829 [cm.sup.-1], owing to the As-O stretching vibration of the As-O-Fe coordination of the ferric arsenate (i.e., scorodite) and the surface complex (i.e., protonated Fe[O.sub.2]As(O)(OH) and unprotonated Fe[O.sub.2]As[(O).sup.2.sup.2-] forms) on the precipitates [35].
Overall, Sican and later pre-Hispanic metal mining in the Lambayeque region of the north coast of Peru was technically simple, labor intensive, and focused on readily accessible outcropped, weathered and enriched, high-grade oxide, carbonate and sulfide ore bodies bearing copper and arsenic (arsenopyrite and scorodite).
It is known that scorodite compounds are favorably formed in acidic solution of Fe (III) and As (V) at high temperature (eg.
The gossan is composed primarily of goethite, quartz (Si[O.sub.2]), beudantite (Pb[Fe.sub.3](As[O.sub.4]) (S[O.sub.4])[(OH).sub.6]), jarosite ((K,Na)[Fe.sub.3][(S[O.sub.4]).sub.2][(OH).sub.6]), plumbojarosite [(Pb[Fe.sub.6](S[O.sub.4]).sub.4][(OH).sub.12]), argentojarosite (Ag[Fe.sub.3][(S[O.sub.4]).sub.2][(OH).sub.6]), bindheimite ([Pb.sub.2][Sb.sub.2][O.sub.6] (O,OH)) and scorodite with accessory cinnabar (HgS), native Ag, Au, and cassiterite (Sn[O.sub.2]) (Boyle 1995).
Looking around optimistically for a fresh lot of those fine scorodite specimens from Hezhou, Guangxi Zhuang Autonomous Region (see the online "what's new" report of May 23, 2008), I was disappointed to find none such, although it should be noted that Marcus Origlieri of Mineral Zone still has a few excellent thumbnails from the original find; the very best of these, with sharp crystals to 1.5 cm, are priced just south of $1000.
The world's best specimens of paradamite and kottigite/parasymplesite have also been found there, as well as superb specimens of aurichalcite, scorodite, hemimorphite, rosasite, wulfenite and other minerals.
Most exciting and promising, surely, among the what's-new items from this year's Dallas Show is a find of superb scorodite in what is said to be a small prospect pit near the town of Hezhou, near the eastern border of Guangxi Zhuang Autonomous Region, southern China.
Scorodite from "Tamdrost" (probably Oumlil, since 2001): highly lustrous, dark blue-green crystals to more than 2 cm.
Of these, Ernesto felt fairly confident in naming scorodite, powellite, lotharmeyerite, and zincroselite, and he suspected that lavendulan, chalcophyllite and sainfeldite were present as well.
A total of several thousand mimetite specimens were recovered, as well as about 30 attractive specimens of scorodite found later in 2003.
Albite Arsenopyrite Azurite Beryl Biotite Bismuth Calcite Cassiterite Chalcopyrite Danburite Dravite Ferberite Ferro-axinite Fluorapatite Fluorite Garnet (almandine?) Goethite Goyazite Hematite Malachite Molybdenite Monazite Muscovite Opal variety hyalite Plumbogummite Pyrite Quartz Rutile Scheelite Schorl Scorodite Titanite Topaz Table 5.