KGS Navigation Bar, Search, Contact, KGS Home, UK Home University of Kentucky at Kentucky Geological Survey at Search KGS at contact kgs at KGS Home at UK Home at KGS Home

KGS Home > Industrial Minerals

Bentonite: A soft, plastic, porous, light-colored rock composed essentially of clay minerals of the montmorillonite group plus colloidal silica, and produced by devitrification and accompanying chemical alteration of a glassy igneous material. (Definition from Jackson, J.A., ed., 1997, Glossary of geology [4th ed.]: Alexandria, Va., American Geological Institute, 769 p.)