Industry uses bentonite more for the physical properties it can develop than for its chemical composition. Accordingly, the greatest tonnage of bentonite is used annually for bonding, plasticizing, or suspending purposes. In these applications, the bentonite is usually in contact with water. Thus the clay-water characteristics are of primary importance to industry. The chemical composition of the bentonite is a consideration only because changes in physical properties accompany changes in chemical composition. There arc some exceptions, and generally these can be described as instances where the clay chemistry, as a component in a product, could be a complicating factor.