AM_Dickite
Formula: Si2 Al2 O9 H4
Name: Dickite
Unit cell: 5.15 8.94 14.736 90.0 103.58 90.0 , V=659.49
Space group: C1C1 (9)

Bailey S W , American Mineralogist , 48 (1963) p.1196-1209, Polymorphism of the kaolin minerals