Bentonite is a kind of fine clay and is normally referred to colloide organic soils that is mixed with Cretaceous Benton Shale near Benton Army Castle and Rock River, Wyoming. Bentonite is a matter under clay or semi-clay category and is formed by swelling minerals that generally contain montmorillonite and a little Beidellite.

As such, Bentonite is a clay with 85-90% montmorillonite. The word “montmorillonite” is derived from a place in the south of France named Mountmorillon that is a rich source of Bentonite. Many of the bentonites are formed as the result of weathered volcanic ashes and mostly with the presence of water. Their stone origin is basic. Volcanic ashes are mostly created in salty and wetlands. As we move farther from the volcano, Bentonite thickness will decrease. Bentonite has an alumina-silicate structure and therefore it is categorized under 3-layered silicates. Bentonite has two tetrahedron and one octahedron layers. Calcium Bentonite is applied for casting sand, oil absorbents and grease, filtration and refinery, and livestock feed.


  • Chemical analysis Bentonite table

    L.O.I Al2O3 MgO CaO Fe2O3 SiO2 Na2O K2O TiO2 CaCO3 Caf2
    Trace 10-13 Trace 3-5 3-4 60-70 Trace Trace Trace Trace Trace