Due to viscosity and plasticity, clays and clay minerals are used in civil engineering, pottery and also in cosmetics and medicine as thickening agents and emulsion and suspension stabilizers. The rheological properties of clay suspensions are complex. Mostly it is an interaction between mineral composition, clay particle size and pH value and also depends on clay minerals. Clay-water suspension is non-Newtonian fluid showing thixotropic and pseudoplastic properties. Results showed that plasticity index varies between the depth of clay samples and the average values in all deposits are 23±2. It was obtained that the viscosity of clay suspensions increases with increasing the concentration of suspension and is inversely proportional to applied speed.