Anthoinite

anthoinite

cassiterite

ferberite

scheelite

Images

Formula: AlWO3(OH)3
Wolframate, forms pseudomorphs after scheelite crystals.
Crystal System: Triclinic
Specific gravity: 4.78 to 4.87 measured, 4.84 calculated
Hardness: 1
Streak: White
Colour: White (when free of iron)
Luminescence:
Solubility: Slowly attacked by hydrochloric and nitric acids, readily soluble in strong KOH solution
Environments

Metamorphic environments
Placer deposits

Localities

At the Kara No. 1 Pit, Kara Mines, Hampshire mining district, Burnie City, Tasmania, Australia, the first occurrence of mpororoite and anthoinite outside the African Continent has been found in an altered skarn, forming a white powdery mixture of the two minerals pseudomorphing scheelite. The thermal treatment of the mixture at 100oC for 6 hours in air brings about the conversion of mpororoite into anthoinite, which re-hydrates into mpororoite, although the associated anthoinite does not. The source of aluminium is ascribed to the decomposition of aluminian andradite in the skarn (MM 48.397-400).

At the Flo property (Kalzas property), Mayo mining district, Yukon, Canada, is associated with ferberite, scheelite, ferritungstite, russellite and mpororoite (HOM).

At the type locality, Mt Misobo Mine, Maniema, DR Congo, anthoinite occurs as powdery to chalky masses, as pseudomorphs after large scheelite crystals and as platy crystals to a few mm in size. It occurs in tin-tungsten placers and in tungsten-bearing quartz veins. Associated minerals include cassiterite, ferberite, quartz, scheelite and wolframite (Mindat).
Anthoinite from Mt Misobo Mine - Image

At the Gifurwe Mines, Gifurwe, Rusarabuge, Burera District, Northern Province, Rwanda, anthoinite is associated with raspite, ferberite and ferritungstite (HOM).

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