- Ball clay
Ball clays are kaolinitic
sedimentary clay s, that commonly consist of 20-80% kaolinite, 10-25%mica , 6-65%quartz . Localizedseam s in the same deposit have variations in composition, including the quantity of the majormineral s, accessory minerals andcarbonaceous materials such aslignite . They are fine-grained and plastic in nature.Ball clays are relatively scarce deposits due to the combination of geological factors needed for their formation and preservation. They are mined in parts of the Eastern United States and from three sites [The Bovey Basin in South Devon, the Petrockstowe Basin in North Devon and the Wareham Basin in South Dorset.] in
Devon andDorset in South WestEngland .cite web
last = Highley
first = David
authorlink =
coauthors = Bloodworth, Andrew; Bate, Richard
title = Ball Clay - Mineral Planning Factsheet
work =
publisher = British Geological Survey
date = 2006
url = http://www.mineralsuk.com/britmin/mpfball_clay.pdf
format = pdf file
accessdate = 2008-08-05] They are commonly used in the construction of many ceramic articles, where their primary role is to either to impart plasticity or to aidrheological stability during the shaping processes.History
The name "ball clay" is believed to derive from the time when the clay was mined by hand. It was cut into 15 to 17-kilogram cubes and during transport the corners of the cubes became rounded off leaving "balls".cite web
title = What is ball clay?
publisher = Industrial Minerals Association - North America
url = http://www.ima-na.org/about_industrial_minerals/ball_clay.asp
accessdate = 2008-08-05]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 and 17th century.cite web
title = The Widespread Use of Ball Clay
work = Introduction to Ball Clays
publisher = The Ball Clay Heritage Society
url = http://www.clayheritage.org/pages/wideuses.htm
accessdate = 2008-08-05] In 1771Josiah Wedgwood signed a contract for 1400 tons a year of ball clay with Thomas Hyde of Purbeck enabling him to fire thinner walled ceramics.cite web
title = History of Ball Clay - Swanage Railway
publisher = The Purbeck Mineral & Mining Museum
url = http://www.pmmmg.org/History.htm
accessdate = 2008-08-05]ee also
Ball clay and the Stover Canal
Notes and references
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