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Formula: Na6MnTi4Si8O28.4H2O
Inosilicate (chain silicate), single chains, manganese- and
titanium- bearing mineral
Crystal System: Orthorhombic
Specific gravity: 2.86 measured, 2.88 calculated
Hardness: 5½ to 6
Streak: White
Colour: Colourless
Luminescence: Not fluorescnt under UV
Environments
Localities
At the type locality, the Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada,
manganokukisvumite formed late in the paragenesis but before the final
zeolite phase, in small cavities in an
albite-rich syenite
breccia. It is associated with
aegirine, microcline,
albite, annite,
pyrite, pyrrhotite,
chalcopyrite, natrolite,
calcite, a chlorite group
mineral, magnetite,
fluorapatite, elpidite,
sodalite, labuntsovite-Mn
and titanite. Manganokukisvumite likely formed through the
hydrothermal dissolution of other titanium-bearing minerals, especially
aegirine, which is strongly enriched in
titanium in this association. Manganokukisvumite is very rare,
occurring sparsely in the breccia cavities as extremely thin, flattened,
sword-shaped crystals to 0.5 mm in length. It typically forms radiating, fan-shaped groups of crystals
(CM 42.3.781-785).
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