Category Cyclosilicate Crystal system Orthorhombic | Strunz classification 9.CE.30a Space group Pbam | |
![]() | ||
Formula(repeating unit) (Na,Ca)(Nb,Ti)Si2O7·2H2O Crystal class Dipyramidal (mmm)H-M symbol: (2/m 2/m 2/m) |
Nenadkevichite is a rare silicate mineral containing niobium with formula: (Na,Ca)(Nb,Ti)Si2O7·2H2O. It forms brown to yellow to rose colored orthorhombic dipyramidal crystals with a dull to earthy luster. It has a Mohs hardness of 5 and a specific gravity of 2.86.
It was first reported in 1955 from a nepheline syenite pegmatite in the Kola Peninsula. In addition it has been reported from Mont Saint-Hilaire, Canada; the Ilimaussaq complex, Greenland; Windhoek District, Namibia; and Zheltye Vody, Ukraine. It was named after Konstantin Avtonomovich Nenadkevich (1880–1963), Russian mineralogist and geochemist.
References
Nenadkevichite Wikipedia(Text) CC BY-SA