Bianchite

minerals

ktenasite

goslarite

melanterite

Formula: Zn(SO4).6H2O
Hydrated normal sulphate, hexahydrite group
Specific gravity: 2.03 to 2.07
Hardness: 2½
Streak: White
Colour: White, yellowish; colourless in transmitted light
Environments

Hydrothermal environments

Bianchite is a post-mining mineral, typically in efflorescences on mine walls, as an alteration product of oxidising sulphides (HOM).

Localities

At the Peelwood mine, Burraga, New South Wales, Australia, a period of drought in 2006 resulted in the drying up of some of the water retention ponds draining the mine workings and dumps. A white crystalline crust coating the lining of one of the ponds was analysed and shown to be mainly magnesium-rich goslarite, wattevilleite, hexahydrite and bianchite (AJM 13.1.42-44).

At the type locality, the Raibl Mines, Cave del Predil, Tarvisio, Udine Province, Friuli-Venezia Giulia, Italy, bianchite forms crusts in artificial caves (AM 15.538). Associated minerals include goslarite, melanterite, hydrozincite and gypsum (HOM).

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