1,Bentonite is absorbent clay consisting mostly of the mineral montmorillonite 2,use:piling, foundry, palletizing cosmetics etc Calcium Bentonite for ... INTRODUCTION:Bentonite is absorbent clay consisting mostly of the mineral montmorillonite. It is formed by the weathering of volcanic ash, ... an impure form of hydrated aluminum silicate. The formula of montmorillonite may be written as (Na,Ca)0.33(Al, ...