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Oxides & Hydroxide

Fergusonite-(Y)

YNbO₄
Hardness5.5–6.5
Crystal systemTetragonal
ClassOxides & Hydroxide
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Fergusonite-(Y) specimen

Fergusonite-(Y) Locality: Ambalabe pegmatite, Manapa pegmatite Field, Betafo District, Vakinankaratra Region , Antananarivo Province , Madagascar ( Locality at mindat.org ) Size: 3.3 x 3.0 x 2.3 cm. Sharp, lustrous, black crystals to 1.0 cm in parallel-growth very nicely set on a glassy cleavage of banded smoky quartz. — Photo: Robert M. Lavinsky · CC BY-SA 3.0

Fergusonite-(Y)

Fergusonite-(Y) is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula YNbO₄.

It crystallizes in the tetragonal crystal system (space group I4_1/a). It is a member of the Scheelite structural group.

Key properties: Mohs hardness 5.5–6.5; specific gravity 5.6–5.8; Brown, yellow-brown, greenish gray streak; Dull; vitreous to submetallic on fractures luster.

IMA symbol Fgs-Y, IMA status: approved, named in 1825.

Typical of rare-earth-bearing granite pegmatites; in placers.

It is found associated with Monazite, gadolinite, thalenite, euxenite, allanite, zircon, biotite, magnetite.

The mineral was named to honor Robert Ferguson (1767–1840), landowner, politician, and mineral collector, of Raith, near Kirkaldy, Scotland, and for its predominant yttrium content.

Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet. Browse more F minerals or help write this entry.