Yttrotantalite-(Y) Locality: Ytterby , Resarö , Vaxholm , Uppland , Sweden ( Locality at mindat.org ) Size: 6.9 x 5.2 x 3.4 cm. Yttrotantalite is a rare, rare earth oxide rich in yttrium and is similar to tantalite. This old-time specimen, with waxy lustre is from the Type Locality - the Ytterby pegmatite in Sweden. The brick-red cubes filling the little vug are pyrite crystals. About 10 rare elements were discovered here. Ex. Mullane Collection and comes with a faded, old label. Classic, old material. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Yttrotantalite-(Y)
Yttrotantalite-(Y) is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (Y,U,Fe²⁺)(Ta,Nb)(O,OH)₄.
It crystallizes in the amorphous crystal system.
Key properties: Mohs hardness 5–5.5; specific gravity 5.7; Gray streak; Submetallic to vitreous, greasy luster.
IMA symbol Yttl-Y, IMA status: approved, named in 1802.
Found as a rare accessory mineral in granite pegmatites.
It is found associated with Albite, garnet, topaz, fergusonite (Ytterby, Sweden); monazite, columbite, allanite, samarskite, xenotime, gadolinite, mica (Norway).
The name refers to YTTRium in its composition and relation to tantalite.