What is "china stone"

n. a fine usually white clay formed by the weathering of aluminous minerals (as feldspar); used in ceramics and as an absorbent and as a filler (e.g., in paper) [syn: china clay, kaolin, kaoline, porcelain clay, terra alba]

China stone is a medium grained, feldspar-rich partially kaolinised granite characterized by the absence of iron-bearing minerals. 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 and is the UK’s only indigenous source of feldspathic material currently being commercially extracted. Production levels 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, which although somewhat similar, is a different rock.