:Very rare, this large, single crystal of yttrocolumbite is exceptional for size, form, and locality. The metallic luster is good. There are four listed localities (this makes five). This species isn’t listed for this region on Mindat. Formerly in the collection of Michael Cohan. Size: 3.5 x 1.9 x 1.2 cm. Locality: Spruce Pine District, Mitchell Co., North Carolina, USA — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Yttrocolumbite-(Y)
Yttrocolumbite-(Y) is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (Y,U,Fe²⁺)(Nb,Ta)O₄.
Key properties: Mohs hardness 5; specific gravity 5.49; Brown streak; Vitreous luster.
IMA symbol Yclb-Y, IMA status: questionable, named in 1837.
[A rare accessory mineral in granite pegmatites.].
As the niobium (columbium) analog of yttrotantalite.