AM_Cordierite_13 Formula: O18.8 Al3.6 Be.4 Si5 (Mg.76 Fe1.1 Li.14) Na.47 H.8 Name: Cordierite Unit cell: 17.065 9.797 9.293 90.0 90.0 90.0 , V=1553.66 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 Kemio Island, Finland