The 18th century fascination with imitating other materials through the use of glazes and enamels on porcelain can clearly be seen in a set of seven thumb rings in the collection of the National Palace Museum, Taipei, each of which imitates a different material, including pudding stone, wood, bamboo, marble, inlaid bronze, malachite and turquoise; see Emperor Ch'ien-lung's Grand Cultural Enterprise, National Palace Museum, Taipei, p. 199, no. V-36.
'Pudding stone' is a generic term applied to any conglomerate sedimentary rock that is characterised by colorful inclusions. The conglomerate is composed of pebbles that have been worn smooth by water and have been cemented together by a finer mineral deposit. This finer mineral deposit fills in the spaces between the pebbles and forms a solid rock.
A Qianlong circular box decorated to look like 'pudding stone' in the collection of the Palace Museum, Beijing is illustrated in Kangxi. Yongzheng. Qianlong - Qing Porcelain from the Palace Museum Collection, Beijing, 1989, p. 424, no. 106.
Another from the Robert H. Blumenfield Collection was sold in our New York Rooms, 25 March 2010, lot 877.