A fine, soft, very plastic clay. Ball clay is a relatively pure, secondary clay composed of kaolin (20-90%), mica (5-45%), and quartz (1-70%). The high quality clay is found in England (Wareham, Dorset, Devon) and the U.S. (Kentucky, Tennessee). Originally, ball clay was dug up and made into 30-35 pound balls for transportation by horses. The fine-grain clay contains small amounts of carbon and other organic materials that give it an intial dark color. These materials are combusted during firing leaving a white vessel. Ball clay is very plastic and has a high shrinkage rate of up to 20 %. It is often mixed with other clays to increase their plasticity. Ball clay is used in the manufacture of ceramics, whiteware, porcelain, glass, and tiles.
Synonyms and Related Terms
argile plastique (Fr.); argila gorda (Port.)
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