Samarskite(Yb). Dimensions: 1 cm x 0.7 cm x 0.4 cm From "Patsy" Pegmatite, South Platte Pegmatite District, Jefferson County, Colorado, U.S.A. Raúl Jorge Tauber Larry´s collection. — Photo: Raúl Jorge Tauber Larry · CC0
Samarskite-(Yb)
Samarskite is a radioactive rare earth mineral series which includes samarskite-(Y), with the chemical formula (YFe3+Fe2+U,Th,Ca)2(Nb,Ta)2O8 and samarskite-(Yb), with the chemical formula (YbFe3+)2(Nb,Ta)2O8. The formula for samarskite-(Y) is also given as (Y,Fe3+,U)(Nb,Ta)O4. Samarskite crystallizes in the orthorhombic – dipyramidal class as black to yellowish brown stubby prisms although it is typically found as anhedral masses. Specimens with a high uranium content are typically metamict and appear coated with a yellow brown earthy rind.
Intro adapted from Wikipedia (CC BY-SA).
Samarskite-(Yb) is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula YbNbO₄.
It crystallizes in the monoclinic crystal system. It is a member of the Samarskite structural group.
IMA symbol Smk-Yb, IMA status: approved, named in 2004.