AM_Offretite_1 Formula: (Si12.6 Al5.4) Ca1.52 K.96 Mg.97 O51.5 H19.678 Name: Offretite Unit cell: 13.39 13.39 7.598 90.0 90.0 120.0 , V=1179.75 Space group: P-6M2 (187)

Gualtieri A , Artioli G , Passaglia E , Bigi S , Viani A , Hanson J C , American Mineralogist , 83 (1998) p.590-606, Crystal structure-crystal chemistry relationships in the zeolites erionite, and offretite, Sample #1 from Fitta