Bentonite is a clay material that is quite
abundant on earth. It was and is still
formed in nature by weathering of
Volcanic ashes and subsequent
sedimentation. Bentonite properties
are determined mainly by the amount
and type of smectite-type layer
silicates, for example montmorillonite.
These minerals consist of stacks of platelet-like crystals that can fully disintegrate in water and form viscous slurries. They also exhibit a high specific surface area and cation exchange capacity, and can thus adsorb and bind quite a variety of molecules. All these properties, and many more, vary from one bentonite deposit to the other, and they can all be influenced by an appropriate treatment of the clay by various processes.