Bentonite

 Bentonite is a clay mineral predominantly consisting of mineral Montmorillonite, mixed with some related minerals like Nontronite and Beidellite.These are three layered Aluminosilicate with molecules of water in between the layers. For natural Sodium Bentonite, exchangeable sodium cations are predominant, rather than other cations like calcium and magnesium. Similarly in Calcium Bentonite, calcium cations are predominant. In fact in all bentonite available in the world, the sodium variety has high swelling and gelling properties along with good viscosity and liquid limit. The bentonite found in the Kutch region of India is of igneous origin. It was formed millions of years ago, possibly from the volcanic ash falling in stagnant saline water in semi-arid conditions. Due to the natural characteristics of these particular volcanic ashes, the chemical composition of this bentonite is somewhat different from the range available in the rest of the world. Most of these deposits are of natural sodium bentonite with higher iron content, which gives them their darker color. Due to the very fine particle size, this bentonite shows extra-ordinary swelling capacity and bonding powers.