AM_Cordierite_15
Formula: O18.75 Al3.84 Be.16 Si5 (Mg1.32 Fe.58 Li.1) Na.27 H.75
Name: Cordierite
Unit cell: 17.054 9.759 9.324 90.0 90.0 90.0 , V=1551.79
Space group: CCCM (66)

Armbruster T , American Mineralogist , 71 (1986) p.746-757, Role of Na in the structure of low-cordierite: A single-crystal X-ray study, Sample: from Haddam, Connecticut, USA