Vonbezingite

minerals

ettringite

sturmanite

bultfonteinite

Formula: Ca6Cu3(SO4)3(OH)12.2H2O
Hydrated sulphate containing hydroxyl
Specific gravity: 2.82
Hardness: 4
Streak: Light blue
Colour: Deep blue
Environments

Evaporite

Vonbezingite is an extremely rare mineral, to date (May 2020) found only at the type locality, where fewer than 50 specimens have been found, the finest of them being 5 cm long (R&M 94.3.250-253).

At the type locality, the Wessels Mine, Hotazel, Kalahari manganese field, Northern Cape, South Africa, vonbezingite was formed during a period of evaporation of surface or groundwaters at ambient temperature and atmospheric pressure (HOM, Dana). It was found in a single solution cavity which was coated with minerals including bultfonteinite, gypsum, calcite, baryte and azurite, but dominated by sturmanite crystals. Dark blue vonbezingite crystals were dispersed among the light-colored minerals lining the cavity. Backscattered electron imaging of vonbezingite showed micrometer-sized inclusions of baryte and azurite (AM 77.1292-1300). Tobermorite, ettringite and thaumasite have also been found in association with vonbezingite (Mindat, R&M 94.3.250-253).

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