In this paper, a new expression for temperature dependence of thermal expansivity and bulk modulus are developed using a simple thermodynamical equation of state. The proposed equation of state is applied to investigate the study thermal expansivity and bulk modulus of various classes of minerals and provides the non-linear models for variation of both thermal expansivity and bulk modulus with temperatures. The results obtained for various earth’s minerals are discussed and compared with experimental results. The computed values of thermal expansivity and bulk modulus have shown a good agreement with available experimental results. It is concluded that a new expression for thermal expansivity and bulk modulus is capable to predict the elastic properties of Earth’s minerals under high temperature conditions.