Bentonite waa dhoobo aluminium phyllosilicate ah oo nuugaya oo ka kooban inta badan montmorillonite. Noocyada kala duwan ee bentonite ayaa mid walba loo magacaabay ka dib curiyaha ugu muhiimsan, sida potassium (K), sodium (Na), calcium (Ca), iyo aluminium (Al). Shirkaddayadu waxay inta badan bixisaa sodium bentonite dabiiciga ah.