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Formula: [Fe,AsO4,SO4,H2O] (?)
Compound arsenate
Crystal System: Amorphous
Specific gravity: 2.2 to 2.5 measured
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:
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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