Yixing clay comes from Yixing town in Jiangsu Province, situated in the delta of the Yangtze River. It is a compound clay rich in minerals such as kaolin, mica, quartz and has high iron oxide content. Used almost exclusively for making teaware, it plays one of the central roles in Gong Fu tea culture. The umbrella name for all the Yixing clays is Zi Sha, which means "purple mud".