By the Shang and Zhou period (17th to 3rd centuries BC) the pottery of the primitive age had been developed into glazed pottery. From then on the ferrous content in the body and the glaze was continuously reduced, until celadon ware gradually emerged in the Wei and Jin period (220-420AD). This was when the Chinese completed the period of transition from earthenware to porcelain.
原始時代的陶器，到了商周時期，發展成釉陶，再不斷減少胎釉中的含鐵量，在魏晉時代逐漸燒成了青瓷，於是中國人在此時完成了由陶到瓷的過渡期。