Craquelure is a fine pattern of dense cracking formed on the surface of materials. It can be a result of drying, shock, aging, intentional patterning, or a combination of all four. The term is most often used to refer to tempera or oil paintings, but it can also develop in old ivory carvings or painted miniatures on an ivory backing. Recently, analysis of craquelure has been proposed as a way to authenticate art.
Craquelure in the Mona Lisa, with a typical "Italian" pattern of small rectangular blocks
Age craquelure in pottery
Typical French craquelure in a portrait from c. 1750, larger and less regular patterns, with curving cracks
American art pottery, vase by Hugh C. Robertson, Dedham Pottery, (CKAW) c. 1886-89, with deliberate crackle glaze in the Chinese style.
Ge ware or Ko ware is a type of celadon or greenware in Chinese pottery. It was one of the Five Great Kilns of the Song dynasty recognised by later Chinese writers, but has remained rather mysterious to modern scholars, with much debate as to which surviving pieces, if any, actually are Ge ware, whether they actually come from the Song, and where they were made. In recognition of this, many sources call all actual pieces Ge-type ware.
Ge-type vase, with "gold thread and iron wire" double crackle, dated by the Palace Museum Beijing to the Song
Ge-type vase, with "gold thread and iron wire" double crackle
18th-century imitation of Ge ware in Jingdezhen porcelain, with single crackle pattern.