Mg2 Fe.1 Al1.27 Si1.4 O4.6 (O H)4.4

Al_1.27Fe_0.1H_4.4Mg₂O₉Si_1.4

Jahanbagloo, I.C.Zoltai, T.

American Mineralogist (1968) 53, 14-24

a=5.295Å   b=5.295Å   c=63.99Å

α=90°   β=90°   γ=120°