Main Page | See live article | Alphabetical index Bentonite is an absorbent aluminum silicate clay formed from volcanic ash that expands when wet and used to make slurry walls. It can be used in cement, adhesives, and ceramic fillers. It is named after Benton Formation (at one time Fort Benton Formation) in eastern Wyoming's Rock Creek area. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.