Abstract: “Montmorillonite is a specific mineral name of the smectite group widely distributed in several states of India. Jharkhand montmorillonites collected from different places have been studied for physico-chemical properties and TGA. Montmorillonite deposits of economic importance occur only in tertiary formations. Jharkhand montmorillonites have got more industrial application due to its good swelling power, adsorption capacity and ion exchange capacity. The exchangeable cations are Ca2+ , Mg2+ ,Na+ and K+. cation exchange capacities are calculated in (meq/100g) for different cations. Clay minerals have a layered structure based on sheets with 6-membered rings of silica tetrahedra. The composition of minerals are SiO2,Al2O3,Na2O,K2O,Fe2O3 and traces of MnO showing colours grey,black and brown. Montmorillonite unit gives blue stain test with benzidine solution. The ratio of SiO2 and Al2O3 varies from one sample to another. The TGA experiments show a loss of mass about 18.9% indicating the”

Keywords: Monmorillonite, Smectite,Cation exchange capacity, TGA