Guérinite

guerinite

realgar

erythrite

jeankempite

Images

Formula: Ca5(AsO3OH)2(AsO4)2.9H2O
Hydrated hydrogen arsenate, paramorph of ferrarisite
Crystal System: Monoclinic
Specific gravity: 2.68 to 2.76 measured, 2.74 calculated
Hardness: 1½
Streak: White
Colour: Colourless
Luminescence: Not fluorescent under UV
Environments

Hydrothermal environments

Guérinite occurs as acicular, bladed or tabular crystals; it is a recent weathering product in oxidising arsenic-rich mineral deposits. Associated minerals include realgar, erythrite, quartz and calcite, and it may be intergrown with jeankempite (Mindat, HOM).

Localities

At the type locality, the Daniel Mine, Neustädtel, Schneeberg, Erzgebirgskreis, Saxony, Germany, guérinite is a post-mine product (Mindat).

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