China stone

China stone or "china clay" is a medium grained, feldspar-rich partially kaolinised granite characterized by the absence of iron-bearing minerals. It is mainly used for making porcelain, hence the name, and coatings for paper. Its discovery in the 18th century was a crucial event in the development of the English porcelain industry. Its mineral content includes quartz, feldspar and mica; accessory minerals include kaolinite and fluorspar. It is found in one area of Cornwall in the United Kingdom, near St Austell, and is the UK’s only indigenous source of feldspathic material commercially extracted. Production in the four years up to 2003 averaged 2,800 tonnes per year.

Other names include Cornish or Cornwall stone. It is sometimes confused with petuntse or "porcelain stone", which although somewhat similar, is a different rock.

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