The use of cobalt to decorate ceramics almost certainly originated in the Middle East, and early Iranian ceramics, traded on the Silk Routes, likely inspired the Chinese to experiment with the pigment. Unlike their Chinese counterparts, Persian and Turkish decorators often used underglaze cobalt in conjunction with a turquoise color made from copper oxide, and because these two pigments tended to smear during firing, they used black iron pigment for finer outlines.
Beginning in the late thirteenth century, when the Mongols ruled both China and Iran, the Middle East became one of China’s most avid markets for blue-and-white ceramics. Small ships, called dhows, made the perilous trip through the Indian Ocean, laden with porcelains. Some local potters attempted to make copies of Chinese styles, but their results look very different because Middle Eastern ceramics are usually made of fritware, a glassy clay composite that is rarely as white as porcelain. Most Persian and Turkish ceramics have a layer of white painted over the clay. Because the underglaze cobalt decorations are painted on top of this white coating, they often look paler and less precise than their Chinese prototypes. Some of the finest later traditions of Middle Eastern ceramic-making exploit the almost wet quality of the white-painted ground, creating wares that feel very sumptuous.
Dish, 18th century. Iznik, Turkey, Ottoman period. Fritware with underglaze cobalt and turquoise decoration under a transparent colorless glaze. Brooklyn Museum