the lamellar eutectic structure tends to change to a degenerated structure. The excess Cu dissolved in the α-phase during solidification has formed small precipitates within the interdendritic area. Figure 8 represents the changes from a lamellar eutectic structure to the continuous structure. From this result, it is obviously seen that Si additions effect directly the phase transformation of the sterling silver alloy. It was shown in the results that no significantly difference between the lamellar eutectic structure and chemical composition of the sterling silver alloys preparing by investment and metal mould casting. However, it is clearly seen that the lamellar eutectic structure is transformed partially to a continuous Cu-Si structure when the Si content is increased to 0.05-0.1wt% and it has completely changed to a continuous Cu-Si structure at 0.3wt%.