It is very important to determine the optimum utility of any limestone deposit according to the physical and mechanical properties. The quality index is a good way for this aim. The physical properties such as porosity, density and water absorption and mechanical properties such as compressive-, tensile-strength and coefficient of dynamic fragmentation, control the optimal use of limestone as building, road construction and cement manufacture. These parameters are determined for several locations in Egypt and the quality index for each location is calculated, and the optimal use is determined.