AM_Vermiculite_4 Formula: Mg1.705 (Si1.43 Al.57) O7.86 H3.1 Name: Vermiculite Unit cell: 5.349 9.255 28.89 90.0 97.12 90.0 , V=1419.17 Space group: C12/C1 (15)

Shirozu H , Bailey S W , American Mineralogist , 51 (1966) p.1124-1143, Crystal structure of a two-layer Mg-vermiculite