China stone (occasionally ''Cornish stone'' or ''Cornwall stone'') is a medium grained,

feldspar Feldspar ( ; sometimes spelled felspar) is a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagiocl ...

-rich partially kaolinised

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

characterised by the absence of

iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...

-bearing minerals. Its mineral content includes

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

, feldspar and

mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into fragile elastic plates. This characteristic is described as ''perfect basal cleavage''. Mica is co ...

; accessory minerals include

kaolinite Kaolinite ( ; also called kaolin) is a clay mineral, with the chemical composition Al2 Si2 O5( OH)4. It is a layered silicate mineral, with one tetrahedral sheet of silica () linked through oxygen atoms to one octahedral sheet of alumina () ...

and

fluorspar Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs scal ...

. It is found in one area near

St Austell Saint Austell (, ; ) is a town in Cornwall, England, United Kingdom, south of Bodmin and west of the border with Devon. At the 2021 Census in the United Kingdom, census it had a population of 20,900. History St Austell was a village centred ...

Cornwall Cornwall (; or ) is a Ceremonial counties of England, ceremonial county in South West England. It is also one of the Celtic nations and the homeland of the Cornish people. The county is bordered by the Atlantic Ocean to the north and west, ...

in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

. It was the last UK sourced feldspathic material to be commercially extracted. A number of varieties, named on the basis of their hardness and physical appearance, were produced. Maximum production was achieved in the early 1950s, with around 70,000 tonnes per annum. The largest producer, English China Clays, ceased production in 1973, when Goonvean Ltd became the sole producer. Due to increasing competition from imported alternatives and a contracting domestic market, sales fell from 8,000 tonnes per year to 2,800 tonnes in 2001. The last quarry closed in 2006. Relatively similar material has been mined, and exported to England for ceramics use, in the

Isle of Man The Isle of Man ( , also ), or Mann ( ), is a self-governing British Crown Dependency in the Irish Sea, between Great Britain and Ireland. As head of state, Charles III holds the title Lord of Mann and is represented by a Lieutenant Govern ...

and

Jersey Jersey ( ; ), officially the Bailiwick of Jersey, is an autonomous and self-governing island territory of the British Islands. Although as a British Crown Dependency it is not a sovereign state, it has its own distinguishing civil and gov ...

.’A Dictionary of Mining, Mineral, and Related Terms’ United States Bureau of Mines, 1968. Pg. 203 China stone is sometimes confused with the Chinese material traditionally known as petuntse as well as other Asian pottery stones. However, although somewhat similar they differ in

mineralogy Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical mineralogy, optical) properties of minerals and mineralized artifact (archaeology), artifacts. Specific s ...

External links

Image unprocessed China stone

References

Igneous rocks Geology of Cornwall English pottery {{petrology-stub

See also

External links

References