Chevkinite

  1. Formula: (Ce,La,Ca,Th)4(Fe2+,Mg)(Fe2+,Ti,Fe3+)2(Ti,Fe3+)2(Si2O7)2O8Mohs scale hardness: 5-5,5 Specific gravity: g/cm3Rare earth elements: CeSILICATES (Germanates) CyclosilicatesReferenceshttp://www.mindat.org/min-6867.html

  2. http://www.mindat.org/min-39614.html