AM_Heulandite-Ca_3 Formula: Na.65 Ca1.848 K.06 (Si13.554 Al4.446) O48.38 H12.38 Name: Heulandite-Ca Unit cell: 17.671 17.875 7.412 90.0 116.39 90.0 , V=2097.24 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: nonexchanged, Atomic parameters from ICSD