This study was to investigate physical properties of the system $Ca(Mg_{1-x}Al_x) (Si_{2-x}Al_x)O_6$ by quenching method. This system $chi$=0.1 to 0.3 had same crystal phase microstructure and similar properties. Bulk density microhardness thermal expansion coefficient and modulus of rupture of these solid solutions were 2.87~2.95g/cm3 850~900kg/$mm^2$, $7.5~7.8{ imes}10^{-6}$/$^{circ}C$ and 1950~1980kg/$cm^2$ respectively.