Kalistrontite

kalistrontite

anhydrite

dolomite

sylvite

Images

Formula: K2Sr(SO4)2
Anhydrous sulphate, palmierite group, palmierite supergroup, strontium-bearing mineral
Crystal System: Trigonal
Specific gravity:
Hardness: 2 to 2½
Colour: Colourless
Solubility: Soluble in water
Environments

Evaporite deposits

Localities

At Pleismar, An der Poststraße, Burgenlandkreis, Saxony-Anhalt, Germany, kalistrontite occurs as an alteration product of celestine, associated with halite, sylvite and anhydrite (HOM).

At the Omongwa salt pan, Aminuis, Omaheke Region, Namibia, kalistrontite is associated with gypsum (HOM).

At the type locality, Alshtan Village, Sterlitamak District, Bashkortostan, Russia, kalistrontite occurs as single crystals, elongated along the prism, up to 20 mm long, and as flattened hexagonal tablets up to 22 mm across, in saline anhydrite containing clay and dolomite and a little sylvite. It was found in a drill core from a depth of 447 m. It was probably formed by reaction of sylvite with solutions containing strontium (AM 48.708-712).

At the York Potash Project, Scarborough, North Yorkshire, England, UK, kalistrontite has been discovered in exceptional quantities in exploration boreholes targeting polyhalite-bearing evaporite deposits. The kalistrontite is associated with anhydrite, polyhalite, halite, magnesite, and traces of celestine at depths of ~1.5 to 1.7 km below the surface. It is present in two general forms.
First as irregularly shaped, millimetre-scale crystals that enclose fine, rounded, irregular crystals of anhydrite, halite and magnesite.
Second as a vein-fill formed of an interlocking mosaic of sub-millimetre scale crystals that are compositionally zoned and again enclose fine rounded anhydrite and halite crystals at vein margins.
Kalistrontite displays largely replacive contact relationships with both the earlier and simultaneously formed anhydrite and halite, but before at least some of the polyhalite. Vein-fill kalistrontite was deposited by mineralising fluids proceeding along fractures, patchily replacing the pre-existing low-porosity anhydrite and halite.
Kalistrontite is essentially stable from ambient temperature to ~960°C; melting occurs from ~960 to 1430°C accompanied by the evolution of SO2 (AM 103.1136–1150).

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