Ball clay
Ball clay is a fine-grained, highly plastic, white-firing clay. The name "ball clay" is believed to have originated because when the clay was mined by hand, it was cut into 15- to 17-kilogram cubes, or "balls," for transport. Ball clay is mined in a few places in the Eastern United States. It is used as a bonding agent in ceramic ware; to impart plasticity to the ceramic object, which usually contains a mixture of ball clay, feldspar, kaolin, quartz, and several other components; and to increase the strength of ceramic ware before it is fired in a kiln. Ball clay is also used in the manufacture of ceramic bathroom fixtures, floor tiles, and wallboard.[1]
Ball clay refers to clay which is mainly kaolinite, but is contaminated with organic matter, and not with iron, during deposition by sedimentation. [2]
Ball clay's primary use is mixing with kaolin clay to prevent brittleness while firing. The lack of iron is important to maintain the white color of ball clay and the materials into which it is mixed.[3]