[Ca18][Ca][Al,Fe]12[Fe,Al]Si18O69(OH)9

Al_9.61Ca_18.97Fe_1.49H_9.43Mg_1.81O₇₈Si_17.74

Ohkawa, M.Armbruster, T.Galuskin, E.

Journal of Mineralogical and Petrological Sciences (2009) 104, 69-76

a=15.576(2)Å   b=15.576(2)Å   c=11.835(2)Å

α=90°   β=90°   γ=90°