Scorodite

scorodite

pharmacosiderite

arsenopyrite

beudantite

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Formula: Fe3+(AsO4).2H2O
Hydrated normal arsenate, variscite group, forms a series with mansfieldite and with yanomamite.
Specific gravity: 3.27
Hardness: 3½ to 4
Streak: Greenish-White
Colour: Green, grey, blue, yellow-brown, nearly colourless, violet; colourless to greenish or in transmitted light.
Solubility: Soluble in acids. Decomposes in strong alkali with separation of hydrous iron oxide.
Common impurities: Al
Environments

Pegmatites
Hydrothermal environments

Scorodite is found sometimes as a primary mineral at hydrothermal deposits, for example Saubach, Germany, but mostly as a secondary mineral. It is a common supergene mineral in areas where primary arsenopyrite-bearing mineralisation is present. It may be the only supergene species present, or in more evolved oxidised deposits it may occur accompanied by pharmacosiderite and a range of base-metal arsenates. It occurs typically as discernably crystalline crusts on part-weathered, crumbly and cracked arsenopyrite (MW). It forms from the oxidation of arsenopyrite or other arsenic-containing minerals, and is associated with pharmacosiderite, beudantite, carminite, dussertite, arseniosiderite, adamite, austinite, vivianite, gypsum and chalcedony (Dana, HOM).

Localities

At Kingsgate, Gough county, New South Wales, Australia, scorodite is formed by the oxidation of arsenopyrite, and occurs as druses on arsenopyrite and quartz (AJM 10.1.10-11).

At Sunny Corner, Roxburgh county, New South Wales, Australia, scorodite is associateted with beudantite, and occasionally with bariopharmacosiderite. Scorodite forms first, then beudantite, then bariopharmacosiderite (AJM 17.1.48).

At Kintore, Broken Hill, Broken Hill district, Yancowinna county, New South Wales, Australia, scorodite occurs in a quartz - garnet rock, sometimes with included carminite. It has also been found rarely as a scorodite - strengite crust on hinsdalite (AJM 3.1.62).

At a prospect on Mount Piper near Broadford, Victoria, Australia, crusts of tiny scorodite crystals occur with arsenopyrite and quartz (R&M 85.3.242-248).

At Mount Moliagul, Moliagul, Central Goldfields Shire, Victoria, Australia, botryoidal crusts and groups of scorodite up to 5 mm have been found in cavities in quartz, associated with pyrite, arsenopyrite and jarosite - natrojarosite (AJM 21.1.44).

At a point about 10 kilometers west of L’Amable Station on the Central Ontario Railway, Hastings County, Ontario, Canada, scorodite occurs with arsenopyrite, realgar, and quartz (R&M 85.3.242-248).

At the Brazil Lake occurrence (Elizabeth Lake Mine), Foster Township, Sudbury District, Ontario, Canada, scorodite pseudomorphs after cobaltite to 1 cm have been collected (R&M 85.3.242-248).

At Chuquicamata Mine, Chuquicamata District, Calama, El Loa Province, Antofagasta, Chile, scorodite is an accessory mineral, apparently after enargite of the primary ore (R&M 85.3.242-248).

At the Pingtouling mine, Liannan county, Qingyuan, Guangdong, China, colour-change scorodite lines cavities in limonite, associated with anglesite, arsenic-bearing siderite and beudantite (Minrec 38.1.30 ).

At the Clara Mine, Oberwolfach, Ortenaukreis, Freiburg Region, Baden-Württemberg, Germany, fine specimens of secondary scorodite occur. Spherical clusters to 1 cm abundantly perched on quartz crystals and fluorite cubes have been found. Ferrihydrite pseudomorphs after scorodite have also been found here (R&M 90.1.47).

The type locality is the Stamm Asser Mine, Graul, Langenberg, Raschau-Markersbach, Erzgebirgskreis, Saxony, Germany.

At Mapimí, Mapimí Municipality, Durango, Mexico, two forms of scorodite were found, one in coarse granular masses with numerous small vugs of crystals, and the other in rounded concretionary masses of compact material abundantly veined by arseniosiderite, or with pockets and cavities of carminite and dussertite (AM 22.482).

At the Ojuela Mine, Mapimí, Mapimí Municipality, Durango, Mexico, scorodite is associated with carminite, dussertite, arseniosiderite, legrandite, adamite and arsenopyrite (R&M 85.3.242-248).

At Oumlil, Zagora Province, Drâa-Tafilalet Region, Morocco, scorodite occurs as 1 mm spherules associated with weathered löllingite, and as world-class colour-change crystals to 15 cm (Minrec 38.5.394).

At Tamdrost, Zagora Province, Drâa-Tafilalet Region, Morocco, scorodite crystals to 3 mm have been found forming coatings on erythrite crystals (Minrec 38.5.394).

At the Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia, crystals of scorodite resembling elongate octahedra to 5 cm occur with a suite of rare minerals including betpakdalite, powellite and gerdtremmelite (R&M 85.3.242-248).

At the Stavoren Mine, Stavoren-Mute Fides, Marble Hall, Sekhukhune District, Limpopo, South Africa, scorodite was found intimately associated with arsenopyrite (R&M 85.3.242-248).

At Burdell Gill, Coombe Height, Caldbeck, Allerdale, Cumbria, England, UK, bladed aggregates of scorodite, less than 0.1 mm, on iron-stained quartz were shown by XRD to be scorodite; they appear to be pseudomorphs after parasymplesite. In the wolframite-bearing quartz vein material from lower down Burdell Gill drusy scorodite occurs with residual arsenopyrite (JRS 8(1).6).

At the Driggith and Sandbed mines, Caldbeck, Allerdale, Cumbria, England, UK, scorodite occurs abundantly as drusy encrustations with bariopharmacosiderite, beudantite, carminite and minor mimetite on specimens from arsenate-rich outcrop workings on the vein between the Driggith and Sandbed mines. Epimorphs of scorodite after arsenopyrite occur on a few specimens (JRS 9.31).

At the east side of higher Roughton Gill, Caldbeck, Allerdale, Cumbria, England, UK, scorodite occurs as crusts which are part of an arsenate-rich assemblage that also includes beudantite, carminite and segnitite (JRS 11.22).

At Arm O'Grain, Coombe Height, Mungrisdale, Eden, Cumbria, England, UK, scorodite was identified by XRD as crusts in hairline fractures in the arsenopyrite- and pyrite-rich rock (JRS 9.51).

At the Dolaucothi Gold Mine, Pumpsaint, Carmarthenshire, Wales, UK, scorodite occurs rarely as coatings on part-weathered arsenopyrite (MW).

At the Dolgellau Goldbelt, Gwynedd, Wales, UK, scorodite is widespread in trace to minor amounts. It has been found at Clogau, Vigra, Cefn Coch, Tyddyn Gwladys and Prince Edward mines, and in pyrite - arsenopyrite bearing boulders in the bed of the Afon Wen. In the Foel Ispri mines, near Llanelltyd, sub-millimetre crusts fill small cavities in pyrite - arsenopyrite rich veinstone (MW).

At Gwaith-yr-Afon Mine, Goginan, Ceredigion, Wales, UK, sparsely scattered crystal aggregates of scorodite have been found associated with limonite and pharmacosiderite on quartz (MW).

At Snowdon, Gwynedd, Wales, UK, scorodite is present at mines around the caldera margin, such as Cwm Bychan near Beddgelert, Llanberis, Moel Fleiddiau near Blaenau Ffestiniog and Ceunant and Tan-y-garth mines near Bethesda. Typically it forms thin microcrystalline crusts in association with iron oxides on decomposing arsenopyrite (MW).

At the California Mine (Great Eastern Mine), Summit City, Meadow Lake District, Nevada county, California, USA, scorodite containing native gold is locally abundant (R&M 85.3.242-248).

At the Crystal No. 8 Mine, Chaffee county, Colorado, USA, scorodite is found in the exposed pegmatite where it occurs with yukonite, bariopharmacosiderite, and arsenopyrite (R&M 85.3.242-248).

At the Charter Oak Mine, Red Mountain District, Ouray county, Colorado, USA, scorodite encrusts enargite (R&M 85.3.242-248).

At the Eagle Bird Mine, Garfield Canyon, and the Idaho Muldoon Mine, both at the Little Wood River District, Blaine county, Idaho, USA, scorodite occurs as microcrystalline crusts associated with anglesite and cerussite (R&M 85.3.242-248).

Near Black Pine, Black Pine District, Cassia county, Idaho, USA, prismatic crystals of scorodite form botryoidal aggregates with cinnabar (R&M 85.3.242-248).

At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, scorodite is rare and has been found as crystals less than one millimetre across coating löllingite masses (R&M 94.6.515).

At the San Rafael mine, Quartz Mountain camp, Lodi Mining District, Lodi Hills, Nye county, Nevada, USA, scorodite occurs either as massive intergrowths or as spongy, finegrained nodules. Associated minerals include arseniosiderite, anglesite, bayldonite, beudantite, carminite, galena, mimetite, plumbojarosite and segnitite. In the stope where pharmacosiderite has been found, peculiar masses to several kilograms in weight consisting almost entirely of very finely crystalline scorodite have been found. In this same stope, well-formed crystals of scorodite to 0.1 mm on limonite have also been found, but they are rare (R&M 85.6.520).

At the Majuba Hill Mine, Antelope Mining District, Pershing county, Nevada, USA, scorodite occurs as attractive groups of 2-mm sky-blue crystals associated with pharmacosiderite, arthurite and chalcocite (R&M 85.3.242-248).

At the Chickering mine, Walpole, Cheshire county, New Hampshire, USA, scorodite has been found as a crust covering the surface of corroded arsenopyrite and löllingite in the single known occurrence (R&M 90.5.420).

At the Miss Pickle Tunnel, Eureka Mining District, Grant county, New Mexico, USA, scorodite has been found as liver-brown masses, rarely forming pseudomorphs after arsenopyrite (R&M 85.3.242-248).

At the pegmatite at the November Mine, Needles, Custer county, South Dakota, USA, scorodite occurs with spessartine and arsenopyrite (R&M 85.3.242-248).

At the Richmond-Sitting Bull Mine, Galena Mining District, Lawrence county, South Dakota, USA, excellent though small scorodite crystals occur with beudantite and pharmacosiderite (R&M 85.3.242-248).

At Gold Hill, Toole County, Utah, USA, scorodite forms bodies of considerable magnitude as an alteration product of arsenopyrite (AM 15.390).

At the Crystal Palace claim, North Bend, King county, Washington, USA, scorodite is found as bright greenish crusts with quartz crystals, pyrite and arsenopyrite (R&M 85.3.242-248).

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