Daubréeite

minerals

bismuth

bismuthinite

bismoclite

Formula: BiO(OH) is the IMA formula, but the pure mineral is not known. BiO(OH,Cl) is a better formula. If OH > Cl the mineral is daubréeite, otherwise it is bismoclite
Oxyhalide, matlockite group
Specific gravity: 6.4 to 6.5
Hardness: 2 to 2½
Colour: Creamy-white, greyish, yellowish-brown, colourless in transmitted light
Solubility: Totally soluble in acids. Re-precipitates upon substantial dilution (Mindat)
Environments

Hydrothermal environments

Daubréeite occurs only as massive material.

Localities

At the type locality, the Constancia mine, Cerro Tazna, Nor Chichas Province, Potosí, Bolivia, daubréeite occurs as a secondary mineral formed by alteration of bismuth or bismuthinite in the oxidation zone of a bismuth deposit, associated with clay minerals (Mindat, HOM).

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