Previously the authors studied proto-porcelain samples from early and middle Shang sites (Wucheng, Zhengzhou, Jingnansi, Panlongcheng and Tonggushan) by means of instrumental neutron activation analysis (INAA) . The results showed them to have a similar chemical composition pattern, which suggested that these proto-porcelain shards might have been produced in the same area around Wucheng. In the present paper, the authors report their new analysis on proto-porcelain shards from sites of middle Shang to early Zhou times (Xiaoshuangqiao, Anyang Yinxu, Zhouyuan, Liulihe and Zhangjiapo). For the samples later than the middle Yinxu period, new composition patterns are detected, which indicates diversity in their provenance. The significantly lower Fe2O3 and lower Tio2 contents of these later samples demonstrate the advance of then proto-porcelain industry. Two samples from Zhouyuan with Al2O3 contents higher than 25% seem to suggest that in addition to porcelain stone other materials might also have been used in proto-porcelain production in the Western Zhou period.
