A fine-textured clay rich in iron, found in 宜兴 yí​xīng, Jiangsu province, which turns reddish-brown or dark purple after firing; used primarily for making unglazed stoneware like teapots.

Unglazed stoneware made from purple clay, especially teapots from 宜兴 yí​xīng (also known as boccaro or buccaro ware)