Brownish black resinous crystal aggregates of the very rare Y-Ta mineral tantalaeschynite-(Y) from the TL in Raposa pegmatite (Raposa Pegmatite, São José do Sabugi, Borborema Province, Paraiba, Brazil). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Tantalaeschynite-(Y)
Tantalaeschynite-(Y) is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Y(Ta,Ti,Nb)₂O₆.
It crystallizes in the orthorhombic crystal system. It is a member of the Aeschynite structural group.
Key properties: Mohs hardness 5.5–6; specific gravity 5.75–6.13; Pale yellowish brown streak; Resinous luster.
IMA symbol Taes-Y, IMA status: approved, named in 1969.
Found in a pegmatite.
It is found associated with Quartz, microcline, biotite, columbite, beryl.
The name refers to an aeschynite with TANTALum greater than titanium in the composition and with yttrium as the dominant rare-earth element.