arseniosiderite

Arseniosiderite was documented from the second oxidation zone, between 28 and 30 levels by Geier et al. (1971). Pinch and Wilson (1977) stated that arseniosiderite "… occurs rarely in the lower [= second] oxidation zone as golden-yellow to dark brown sub-metallic crystals in radial aggregates and granular masses and crusts associated with carminite and other arsenates."

Keller (1984) listed arseniosiderite as one of several arsenates associated with anglesite at the relatively low pH / early-formed end of his hauptsequenz [= main sequence] paragenesis. The minerals in this association include anglesite, arsentsumebite, beaverite, beudantite, carminite, corkite, brochantite, chenevixite, ‘mineral TK’ [= gartrellite], pharmacosiderite, powellite and scorodite.

Keller and Innes (1986) considered that arseniosiderite is a late-forming mineral, sometimes as an alteration product from ludlockite.

Bowell and Mocke (2018) identified arseniosiderite in assemblages from the first oxidation zone (levels 4 and 6), the second oxidation zone (levels 29, 32 and 34), and the third oxidation zone (Level 42), in specimens from the collection of the Geological Survey of Namibia. They commented that arseniosiderite has commonly been misidentified as goethite or limonite and they considered that arseniosiderite is widespread at Tsumeb. Further confirmation of the provenance of specimens from this study and the means of identification is desirable.

A specimen formerly in the Lammer Collection (# 2834) includes botryoidal aggregates of yellow to brown arseniosiderite in association with goethite, hematite, ludlockite, ojuelaite, quartz, schneiderhöhnite and scorodite.

anglesite; arsendescloizite; arsentsumebite; beaverite-(Cu); beudantite; brochantite; carminite; corkite; chenevixite; gartrellite; goethite; hematite; ludlockite; ojuelaite; pharmacosiderite; powellite; quartz; schneiderhöhnite; scorodite; tsumcorite