Bentonite 325 (Sodium Bentonite) is used to keep particulates in suspension in glazes, and makes applied glazes harder. Because of it's electrolytic behavior and fine particle size, bentonite is extremely high in plasticity (and thus high shrinkage). In clay bodies it aids plasticity normally lacking in whiter clays. Also called sodium bentonite. Often used for agricultural and landscaping purposes as well in sealing ponds.