AM_Heulandite-Na Formula: Na3.6 (Si13.554 Al4.446) O48.96 H10.96 Name: Heulandite-Na Unit cell: 17.767 17.977 7.422 90.0 116.14 90.0 , V=2128.11 Space group: C12/M1 (12)

Gunter M E , Armbruster T , Kohler T , Knowles C R , American Mineralogist , 79 (1994) p.675-682, Crystal structure and optical properties of Na- and Pb-exchanged, heulandite-group zeolites, Sample: Na-exchanged, Atomic parameters from ICSD