from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. An absorbent aluminum silicate clay formed from volcanic ash and used in various adhesives, cements, and ceramic fillers.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. Any of several impure clay minerals consisting mostly of montmorillonite.
  • n. A porous clay formed by the decomposition of volcanic ash that swells 5 to 6 times its original volume in the presence of water.

from the GNU version of the Collaborative International Dictionary of English

  • n. an absorbent aluminum silicate clay formed from volcanic ash.

from The Century Dictionary and Cyclopedia

  • n. A variety of clay occurring extensively in the Fort Benton strata of the Cretaceous of Wyoming.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. an absorbent aluminum silicate clay formed from volcanic ash


After Benton Formation (formerly Fort Benton Formation) of the Rock Creek district in eastern Wyoming.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Benton +‎ -ite, after the place it was first mined: Fort Benton, Montana. (Wiktionary)


  • Bentonite is a primary montmorillonite clay mined in the U.S.A., but the term bentonite is often used for other commercial montmorillonite clays as well.

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  • Sodic bentonite is a type of clay that swells to many times its dry volume when wet.

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  • Second, there is an additive in that anthrax, bentonite, which is used to cause the anthrax to not stick together, and float in the air.


  • Some investigators think a clay called bentonite was used in the process.

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  • Most conventional cat litter is made from natural clay, or sodium bentonite, which is formed into pellets and dried.

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  • Surround containers with an impermeable backfill such as bentonite clay if the repository is wet.

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  • HEMMER: We've been trying for a couple of days, tossing around this word "bentonite," Major Garrett talked about, this morning, the White House saying it was not present.

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  • Please do not confuse Pascalite with ordinary clays such as bentonite clay, Jordan clay or French green clay.

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  • This filtering, aka fining, is typically performed with fish-bladder isinglass or egg whites, although some companies now choose vegan alternatives such as bentonite clay, silica gel, diatomaceous earth and Irish moss, a seaweed product also known as carrageenan.

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  • There are many concrete repair products out there, but my personal favorite for this situation is a powder that contains Portland cement, bentonite clay and some other ingredients that cause the patching material to harden and expand at the same time.

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