Aeschynite-(Ce)

minerals

allanite

monazite

fersmite

Formula: (Ce,Ca,Fe,Th)(Ti,Nb)2(O,OH)6
Multiple oxide containing niobium or titanium, aeschynite group, forms series with nioboaeschynite-(Ce) and with aeschynite-(Y) (Mindat ).

Specific gravity: 5.19
Hardness: 5 to 6
Streak: Nearly black to brown
Colour: Black, brown, light brown to yellow
Common impurities: REE,Sn
Environments

Plutonic igneous environments
Pegmatites
Carbonatites
Placer deposits
Metamorphic environments

Aeschynite-(Ce) occurs in nepheline syenite, in granite pegmatites and in carbonatites in alkaline rocks; it is also a detrital mineral in placers. It is often metamict. Associated minerals include feldspar, zircon, samarskite, columbite, allanite and titanite (HOM, Mindat).

Localities

The type locality is the Gadolinite Pit, Chelyabinsk Oblast, Russia.

At the Dark Star claim, Ravalli county, Montana, USA, aeschynite-(Ce) occurs in carbonatite rocks associated with allanite, apatite, monazite, fersmite, magnetite, pyrite and columbite (Dana).

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