Formula: BaMg(CO3)2
Anhydrous normal carbonate, dolomite group
Specific gravity: 3.84
Hardness: 3½
Streak: White
Colour: Colourless, cloudy white
Solubility: Insoluble in water but readily decomposed by cold dilute hydrochloric acid

Metamorphic environments
Hydrothermal environments

Norsethite is a primary mineral in carbonatites, and uncommon in metamorphosed hydrothermal mineral deposits (HOM).


At the Rosh Pinah Mine, Rosh Pinah, Oranjemund, ǁKaras Region, Namibia, norsethite has been found in large quantities in a zinc-lead-copper deposit. It is one of the major gangue minerals of the deposit, is closely associated with calcite and is apparently of hydrothermal origin. Associated barium-bearing minerals include celsian, baryte, barytocalcite and benstonite (AM 52.1770-1775).

The type locality is the Westvaco mine, Green River formation, Sweetwater county, Wyoming, USA. Here norsethite was found in bentonite-hosted dolomitic black oil shale below the main trona bed, associated with shortite, labuntsovite, searlesite, loughlinite, pyrite and quartz. It also occurs there in grey shale with abundant shortite and northupite, some searlesite and loughlinite, in a fine-grained matrix consisting essentially of quartz and pyrite. Norsethite occurs as circular plates or flattened rhombohedral crystals, 0.2 to 2.0 mm across (AM 46.420-429). Other associated minerals include witherite northupite, leucosphenite dolomite, calcite and barytocalcite (Mindat, HOM).

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