AM_Preiswerkite_1 Formula: Si2 Al3.15 Mg1.85 Na.85 O12 H2 Name: Preiswerkite Unit cell: 5.228 9.049 9.819 90.0 100.41 90.0 , V=456.87 Space group: C12/M1 (12)

Oberti R , Ungaretti L , Tlili A , Smith D C , Robert J-L , American Mineralogist , 78 (1993) p.1290-1298, The crystal structure of preiswerkite, Sample: KP17