Arsenocrandallite

arsenocrandallite

parnauite

mansfieldite

bariopharmacosiderite

Images

Formula: CaAl3(AsO4)(AsO3OH)(OH)6
Hydrated arsenate containing hydroxyl, dussertite group
Crystal System: Trigonal
Specific gravity: 3.25 measured, 3.30 calculated
Hardness: 5½
Streak: White
Colour: White, creamy yellowish white, also blue to bluish green
Luminescence: Not fluorescent under UV
Solubility: Partially dissolved by cold 1:1 hydrochloric or nitric acid, and dissolves slowly in hot 1:1 hydrochloric acid (Dana)
Environments

Hydrothermal environments

Arseocrandallite occurs in the secondary oxidation zone of hydrothermal deposits (Mindat)

Localities

At the type locality, Neubulach, Calw, Karlsruhe Region, Baden-Württemberg, Germany, arsenocrandallite was found as a secondary mineral on specimens from the mine dump. It forms reniform crusts and spherulitic aggregates up to 0.1 mm. Associated minerals include brochantite, chalcophyllite, parnauite, arseniosiderite, mansfieldite, bariopharmacosiderite, bulachite, azurite, malachite, baryte, goethite, quartz and corroded tennantite (AM 67.854, HOM).

At the Centennial Eureka Mine, Eureka, Tintic Mining District, Juab County, Utah, USA, arsenocrandallite is associated with arsenogoyazite, beudantite and olivenite (HOM).

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