Formula: Zn(SO4).6H2O
Hydrated normal sulphate, hexahydrite group
Crystal System: Monoclinic
Specific gravity: 2.03 to 2.07 measured, 2.00 calculated
Hardness: 2½
Streak: White
Colour: White, yellowish; colourless in transmitted light
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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