Grains of Proshchenkoite-(Y) (Grain size up to 0.3 mm) Locality: Tommot, Yakutia, Russia — Photo: Thomas Witzke · CC BY-SA 3.0 de
Proshchenkoite-(Y)
Proshchenkoite-(Y) is an IMA-recognized mineral species in the silicate class, with the chemical formula (Y,REE,Ca,Na,Mn)₁₅Fe²⁺Ca(P,Si)Si₆B₃(O,F)₄₈.
It crystallizes in the hexagonal crystal system (space group R3m). It is a member of the Okanoganite structural group.
Key properties: Mohs hardness 5; specific gravity 4.72; Light brown streak; Vitreous to greasy luster; optically uniaxial.
IMA symbol Pck-Y, IMA status: approved, named in 2008.
Found in pegmatites and the enclosing crystalline schists and aegirinized gneisses.
It is found associated with Chevkinite, fergusonite, gadolinite, britholite, alkali amphibole, fluorite, pyrite, molybdenite.
The mineral was named to honor Evgeniy Grigor’evich Proshchenko (1929-1996), Russian mineralogist and senior author of the first paper about the material now a new species.