Pitticite

pitticite

haidingerite

melanterite

arsenopyrite

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Formula: [Fe,AsO4,SO4,H2O] (?)
Compound arsenate
Specific gravity: 2.2 to 2.5
Hardness: 2 to 3
Streak: Yellow to white
Colour: Yellowish, reddish-brown, brownish red to brownish black, grey, nearly white; pale yellowish to reddish brown in transmitted light
Solubility: Readily soluble in acids. Decomposed by strong alkalies, leaving a residue of iron oxide.
Environments:

Hydrothermal environments

Pitticite is a late secondary mineral typically formed by oxidation of earlier arsenic-bearing species such as arsenopyrite, realgar and orpiment; it may be deposited from mine and spring waters (Mindat). Associated minerals include haidingerite, pharmacolite, pharmacosiderite, diadochite, scorodite, erythrite, melanterite, gypsum, alunite and limonite (HOM, Mindat).

Localities

The type locality is the Christbescherung mine, Großvoigtsberg, Großschirma, Mittelsachsen, Saxony, Germany.

At the White Caps mine, Manhattan, Manhattan Mining District, Toquima Range, Nye county, Nevada, USA, pitticite was found as a secondary formation of crusts upon the limestone walls and floor, and as thin seams in melanterite or small globular forms upon melanterite stalactites. Below both the pitticite and the melanterite is a growth of epsomite crystals. The source of the constituents of the pitticite is a thin bedded pyrite-rich limestone. It may be the result of the oxidation of pyrite in the limestone, the iron sulphate so generated reacting with realgar which is abundantly present in this portion of the mine, or it may be the result of the direct oxidation of arsenopyrite (AM 12.290-292).

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