Fergusonite-(Nd)

fergusonite-(Nd)

ferriallanite-(Ce)

aegirine

niobium

Images

Formula: NdNbO4
Niobate, neodymium-bearing mineral
Crystal System: Tetragonal
Hardness: 5½ to 6½
Colour: Dark brown
Environments

Sedimentary environments
Metamorphic environments

Fergusonite-(Nd) is probably a valid mineral species, but it has never been submitted to the IMA (as of August 2025).

Localities

Originally described, in 1981, from the Bayan Obo deposit, Bayan Obo, Darhan Muminggan United Banner, Baotou League, Nei Mongol Autonomous Region, China. Fergusonite-(Nd) formed at a late stage in the rare earth deposit, where it occurs in aegirine veinlets as dark brown, granular or equant grains with an adamantine lustre; it is typically metamict (AM 74.946-947).

At Ust'-Biraya, Biraya Fe-REE ore occurrence, Biraya and Bya Rivers confluence area, Vitim Plateau, Irkutsk Oblast, Russia, fergusonite-(Nd) occurs with ferriallanite-(Ce) (Mindat photo).
Fergusonite-(Nd) - Image

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