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Formula: Mn2+(Ti,Nb)5O12.9H2O (?)
Multiple oxide, manganese-, titanium- and
niobium-
bearing mineral, forms a series with
manganbelyankinite
Crystal System: Amorphous
Specific gravity: 2.52 to 2.58 measured
Hardness: 2
Colour: Brown to grey or light grey
Environments
Pegmatites
Hydrothermal environments
Gerasimovskite occurs as a secondary mineral formed
by the late-stage hydrothermal alteration of niobium –
titanium minerals (possibly
epistolite)
within ussingite-bearing
pegmatites, associated with alkaline intrusions
(HOM).
Localities
At the Ilímaussaq complex, Kujalleq, Greenland, gerasimovskite is associated with
albite,
analcime, aegirine,
natrolite,
chkalovite, lithian
mica, epistolite,
niobophyllite, monazite,
rhabdophane, tugtupite,
nenadkevichite and
beryllite
(HOM).
Gerasimovskite from the Ilímaussaq Complex -
Image
At the type locality, Malyi Punkaruaiv Mountain, Lovozersky District, Murmansk Oblast, Russia,
gerasimovskite occurs in platy masses in
ussingite-bearing
pegmatites. It is believed to have formed by the
hydrothermal alteration of minerals of the murmanite -
lomonosovite series
(AM 43.1221). Associated minerals include ussingite,
epistolite,
steenstrupine-(Ce) and
neptunite
(HOM).
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