AM_Fluoro-eckermannite_2 Formula: Si8 Mg5.92 Ti.18 Na1.83 O22 F2 Name: Fluoro-eckermannite Unit cell: 9.691 17.93 5.284 90.0 102.98 90.0 , V=894.69 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: Ti, Na.85Na1.02Mg.98Mg4.83Ti.17Si8O22F2