Gerasimovskite

gerasimovskite

ussingite

epistolite

steenstrupine-(Ce)

Images

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 niobiumtitanium 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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