Zeolites are 

Explanation

Zeolites are metal aluminosilicates with some water of hydration. These can be represented by the general formula `M_("x")[(AIO_(2))_("x")(SiO_(2))_(y)]_(n).zH_(2)O` where n is the charge on metal cation.
Permutit `Na_(2)[(AIO_(2))_(2)(SiO_(2))_(2)].xH_(2)O` is an example of zeolite.