'Ball clay's are kaolinitic sedimentary clays, that commonly consists of 20-80%
kaolinite, 10-25%
mica, 6-65%
quartz. Localized seams in the same deposit have variations in composition, including the content of the amount major minerals, accessory minerals and the carbonaceous materials such as
lignite. They are fine-grained and plastic in nature.
Ball clays are mined in many areas of the world including parts of the Eastern United States and
Dorset &
Devon in the
United Kingdom.
[1] Together with other materials they are common raw materials for many ceramic articles, where their primary roles is to either to impart plasticity or to aid
rheological stability during the shaping processes.
History
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. During transport the corners of the cubes rounded off leaving "balls".
[2]
The ceramic use of ball clays in
Britain dates back to at least the Roman era. More recent trade began when a clay was needed to construct
tobacco pipes in the 16th - 17th century.
[3] In
1771 when
Josiah Wedgwood was known to have purchased 1400 tons of ball clay enabling him to fire thinner walled ceramics.
[4]
See also
Ball clay and the Stover Canal
References
1. http://www.mineralsuk.com/britmin/mpfball_clay.pdf
2. http://www.ima-na.org/about_industrial_minerals/ball_clay.asp
3. http://www.clayheritage.org/
4. http://www.pmmmg.org/History.htm