AM_Prehnite Formula: Ca2 Al2 Si3 O12 H2 Name: Prehnite Unit cell: 4.646 5.483 18.486 90.0 90.0 90.0 , V=470.91 Space group: PNCM (53)

Papike J J , Zoltai T , American Mineralogist , 52 (1967) p.974-984, Ordering of tetrahedral aluminium in prehnite, Ca2(Al,Fe)[Si3AlO10](OH)2