Erythrite
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameErythrite
Chemical FormulaCo3(AsO4)2·8H2O
Mohs Hardness2
Crystal Systemmonoclinic
Lusterpearly
Streak Colorpale red to reddish-pink
Cleavageperfect on {010}
Fractureuneven
Specific Gravity3.1
Colorscrimson, peach-red, pink, purple, colorless
Transparencytransparent to translucent
Type LocalityBou Azzer District, Tazenakht, Ouarzazate Province, Souss-Massa-Draâ Region, Morocco
Mineral GroupArsenates
Usescollector's mineral, minor ore of cobalt
Associated Mineralscobaltite, skutterudite, annabergite, native bismuth, arsenopyrite, quartz, calcite
Rarityuncommon
Description
Erythrite typically forms as radiating aggregates of acicular (needle-like) to prismatic crystals, often in vibrant shades of crimson, pink, or peach-red, as seen in this specimen.
Geological Context
Erythrite is a secondary mineral that forms in the oxidation zones of cobalt-bearing arsenide deposits, resulting from the alteration of primary cobalt arsenide minerals.
