Hydrated arsenate containing hydroxyl
Forms pseudomorphs after siderite and scorodite
Specific gravity: 3.60
Hardness: 4½, 1½ in fibres
Colour: Golden-yellow to yellow-brown, reddish-brown, brown, black; reddish brown to brownish yellow in transmitted light
Solubility: Readily soluble in hot acids
Arseniosiderite is a rare secondary mineral formed by the
low-temperature oxidation of earlier arsenic-bearing minerals, such as
Associated Minerals at the type locality include quartz,
psilomelane, hematite and
At Hūttenberg, Carinthia, Austria, arseniosiderite occurs in felted masses with scorodite, symplesite, pitticite and pharmacolite on löllingite.
At Romanêche-Thorins, Saône et Loire, France, arseniosiderite occurs in a manganese deposit with quartz, goethite, romanèchite and psilomelane (Dana).
At Schneeberg, Bavaria, Germany, arseniosiderite occurs with erythrite and roselite Dana.
At the Jesus Maria Mine, Mazapil district, Mexico, arseniosiderite occurs with pharmacolite, chrysocolla and calcite, and as pseudomorphs after scorodite. (Dana)
At the Carrock mine, Caldbeck Fells, Cumbria, England, UK, arseniosiderite occurs as aggregates coating quartz and arsenopyrite, probably formed by the alteration of scorodite (C&S).
At Ingray Gill, Caldbeck Fells, Cumbria, England, UK, arseniosiderite occurs with scorodite, pharmacosiderite and erythrite, and is almost certainly derived from the alteration of erythrite (C&S).
At Nether Row Brow, Caldbeck Fells, Cumbria, England, UK, arseniosiderite has been found with scorodite, beudantite and carminite, probably formed by the alteration of scorodite (C&S).
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