Ball Clay and Kaolin differ only in the degree of plasticity. Kaolin is less plastic than ball clay. Ball Clay is a highly plastic variety of kaolin, but it has very poor plasticity making it difficult to work with.
Ball clays are kaolinitic clays that commonly consist of 20–80% kaolinite, 10–25% mica, 6–65% quartz, as well as organic matter. Ball clay is formed from the weathering and transportation by water of parent rocks. Seams in the same deposit will vary in composition, depending on the quantity of the principal and accessory minerals.
Ball clays are fine-grained, highly plastic clays, which are principally used in the manufacture of ceramic whiteware and sanitaryware where they are appreciated for their plasticity, unfired strength and their light colour on firing. Selected clays can even give pure white end products.
Among others, ball clays are also used in refractories, in polymers, in adhesives and sealants and in horticulture as soil amendments.