AM_Fluoro-eckermannite_1 Formula: Si8 Mg4 Sc1.06 Na3.65 O22 F2 Name: Fluoro-eckermannite Unit cell: 9.82 18.036 5.29 90.0 103.64 90.0 , V=910.51 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: Sc, Na.92Na1.97Mg.03Mg3.95Sc1.05Si8O22F2