AM_Omphacite Formula: Si4 Mg.805 Fe.31 Al.885 (Na.835 Ca1.165) O12 Name: Omphacite Unit cell: 9.596 8.771 5.265 90.0 106.93 90.0 , V=423.93 Space group: P121 (3)

Clark J R , Papike J J , American Mineralogist , 53 (1968) p.840-868, Crystal-chemical characterization of omphacites