This circular piece of clay is used to support and separate the porcelain wares during the firing process. Kilns of both the Yuan and Ming periods have been found at Zulonggong, which produced some of the finest white wares in Dehua. Porcelain from Dehua was known to the Chinese as ‘zhuyoubai’ (pork-grease white) or ‘xiangyabai’ (ivory white), and to the Europeans as ‘blanc de chine’. The high quality of Dehua porcelain was due largely to the exceptional purity of its local porcelain stone. Export wares made for the European market became internationally famous and eventually provided the catalyst for the invention of true porcelain in Europe.