AM_Cummingtonite_7 Formula: Fe3.471 Mg3.445 Al.008 Ca.076 Si8 O24 Name: Cummingtonite Unit cell: 9.522 18.1833 5.3184 90.0 102.02 90.0 , V=900.65 Space group: C12/M1 (12)

Yang H , Hazen R M , Prewitt C T , Finger L W , Lu R , Hemley R J , American Mineralogist , 83 (1998) p.288-299, High-pressure single-crystal X-ray diffraction and infrared spectroscopic