Phase-D (Al-rich)

Al_1.33Fe_0.21Mg_0.16O₆Si_0.91

Boffa Ballaran, T.Frost, D. J.Miyajima, N.Heidelbach, F.

American Mineralogist (2010) 95, 1113-1116

a=4.7621Å   b=4.7621Å   c=4.2964Å

α=90°   β=90°   γ=120°