AM_Niocalite
Formula:
Ca7 Nb Si4 O17 F
Name:
Niocalite
Unit cell:
10.863 10.431 7.37 90.0 110.1 90.0 , V=784.25
Space group:
P1A1 (7)
Mellini M , Tschermaks Mineralogische und Petrographische Mitteilungen , 30 (1982) p.249-266, Niocalite revised: Twinning and crystal structure, Note: cuspidine structure, Locality: Oka, Quebec, Canada