AM_Fluoro-eckermannite_6 Formula: Si8 Mg5.8 Ga.14 Na2.02 O22 F2 Name: Fluoro-eckermannite Unit cell: 9.666 17.902 5.272 90.0 102.84 90.0 , V=889.46 Space group: C12/M1 (12)

Oberti R , Hawthorne F C , Camara F , Raudsepp M , American Mineralogist , 84 (1999) p.102-111, Unusual M3+ cations in synthetic amphiboles with nominal fluoro-eckermannite, composition: Deviations from stoichiometry and structural effects of the, cummingtonite component, Sample: Ga, Na.94Na1.07Mg.93Mg4.87Ga.13Si8O22F2