Pale brown crystals of belyankinite from the type locality (Khibiny Massif, Kola, Russian Federation) and one of the only four known localities worldwide. — Photo: David Hospital · CC BY-SA 4.0
Belyankinite
Belyankinite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Ca₁₋₂(Ti,Zr,Nb)₅O₁₂·9H₂O.
Key properties: Mohs hardness 2–3; Vitreous to oily, pearly on cleavage surfaces luster; optically biaxial.
IMA symbol Byn, IMA status: questionable, named in 1950.
Included in aegirine and microcline, in nepheline syenite pegmatite in an alkalic massif, in part probably as a replacement of murmanite.
It is found associated with Aegirine, microcline, nepheline, zeolites, eudialyte, lorenzenite, lamprophyllite, titanium oxides.
The name refers to Dmitry Stepanovich Belyankin (1876-1953), prominent Russian mineralogist and petrographer.