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China Stone
China stone (occasionally ''Cornish stone'' or ''Cornwall stone'') is a medium grained, feldspar-rich partially kaolinised granite characterised 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 near St Austell, Cornwall in the United Kingdom. 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 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ''plagioclase'' (sodium-calcium) feldspars and the ''alkali'' (potassium-sodium) feldspars. Feldspars make up about 60% of the Earth's crust and 41% of the Earth's continental crust by weight. Feldspars crystallize from magma as both intrusive and extrusive igneous rocks and are also present in many types of metamorphic rock. Rock formed almost entirely of calcic plagioclase feldspar is known as anorthosite. Feldspars are also found in many types of sedimentary rocks. Etymology The name ''feldspar'' derives from the German , a compound of the words ' ("field") and ("flake"). had long been used as the word for "a rock easily cleaved into flakes"; was introduced in the 18th century as a more specific term, referring perhaps to its comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, Devon to the east, and the English Channel to the south. The largest urban area is the Redruth and Camborne conurbation. The county is predominantly rural, with an area of and population of 568,210. After the Redruth-Camborne conurbation, the largest settlements are Falmouth, Cornwall, Falmouth, Penzance, Newquay, St Austell, and Truro. For Local government in England, local government purposes most of Cornwall is a Unitary authorities of England, unitary authority area, with the Isles of Scilly governed by a Council of the Isles of Scilly, unique local authority. The Cornish nationalism, Cornish nationalist movement disputes the constitutional status of Cornwall and seeks greater autonomy within the United Kingdom. Cornwall is the weste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of Cornwall
The geology of Cornwall, England, is dominated by its granite backbone, part of the Cornubian batholith, formed during the Variscan orogeny. Around this is an extensive metamorphic aureole (known locally as killas) formed in the mainly Devonian slates that make up most of the rest of the county. There is an area of sandstone and shale of Carboniferous age in the north east, and the Lizard peninsula is formed of a rare section of uplifted oceanic crust. Coasts Cornwall forms the tip of the south-west peninsula of the island Great Britain, and is therefore exposed to the full force of the prevailing winds that blow in from the Atlantic Ocean. The coastline is composed mainly of resistant rocks that give rise in many places to impressive cliffs. The north and south coasts have different characteristics. The north coast is more exposed and therefore has a wilder nature. The prosaically-named ''High Cliff'', between Boscastle and St Gennys, is the highest sheer-drop cliff i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, as well as their utilization. History Early writing on mineralogy, especially on gemstones, comes from ancient Babylonia, the ancient Greco-Roman world, ancient and medieval History of China, China, and Sanskrit texts from History of India, ancient India and the ancient Islamic world. Books on the subject included the ''Naturalis Historia, Natural History'' of Pliny the Elder, which not only described many different minerals but also explained many of their properties, and Kitab al Jawahir (Book of Precious Stones) by Persian scientist Al-Biruni. The German Renaissance specialist Georgius Agricola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petuntse
Petuntse (from zh, c=白墩子, p=báidūnzì), also spelled petunse and ''bai dunzi'', ''baidunzi'', is a historic term for a wide range of micaceous or feldspathic rocks. However, all will have been subject to geological alteration of igneous rocks that result in materials which, after processing, are suitable as a raw material for some ceramic formulations. The name means "little white bricks", referring to the form in which it was transported to the potteries (compare ball clay). It was, and to some extent continues to be, an important raw material for porcelain. The name ''Pottery stone'' is now used. The alternative name of ''Porcelain stone'' is occasionally used. According to one source, it is mixed with kaolin in proportions varying according to the grade of porcelain to be produced; equal quantities for the best and two thirds petuntse to one third kaolin for everyday ware. There were large deposits of high-quality stone in Jiangxi province in south-eastern China, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 government institutions, so qualifies as a small nation or island country. Located in Northwestern Europe, off the coast of north-west France, it is the largest of the Channel Islands and is from Normandy's Cotentin Peninsula. The Bailiwick consists of the main island of Jersey and some surrounding uninhabited islands and rocks including Les Dirouilles, Les Écréhous, Les Minquiers, and Les Pierres de Lecq. Jersey was part of the Duchy of Normandy, whose dukes became kings of England from 1066. After Normandy was lost by the kings of England in the 13th century, and the ducal title surrendered to France, Jersey remained loyal to the English Crown, though it never became part of the Kingdom of England. At the end of the Napoleonic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Governor. The government of the United Kingdom is responsible for the Isle of Man's military defence and represents it abroad, but the Isle of Man still has a separate international identity. Humans have lived on the island since before 6500 BC. Gaelic cultural influence began in the 5th century AD, when Irish missionaries following the teaching of St Patrick began settling the island, and the Manx language, a branch of the Goidelic languages, emerged. In 627, King Edwin of Northumbria conquered the Isle of Man along with most of Mercia. In the 9th century, Norsemen established the thalassocratic Kingdom of the Isles, which included the Hebrides and the Northern Isles, along with the Isle of Man as the southernmost island. Magnus Bar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, Scotland, Wales and Northern Ireland. The UK includes the island of Great Britain, the north-eastern part of the island of Ireland, and most of List of islands of the United Kingdom, the smaller islands within the British Isles, covering . Northern Ireland shares Republic of Ireland–United Kingdom border, a land border with the Republic of Ireland; otherwise, the UK is surrounded by the Atlantic Ocean, the North Sea, the English Channel, the Celtic Sea and the Irish Sea. It maintains sovereignty over the British Overseas Territories, which are located across various oceans and seas globally. The UK had an estimated population of over 68.2 million people in 2023. The capital and largest city of both England and the UK is London. The cities o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 around the parish church, until the arrival of significant tin mining in the 18th century turned it into a town. St Austell is named after the 6th-century Cornish saint, St Austol, a disciple of St Mewan. In a Vatican manuscript there is a 10th-century list of Cornish parish saints. This includes Austoll, which means that the church and village existed at that time, shortly after 900. St Austell is not mentioned in Domesday Book (1086). However, A. L. Rowse, in his book ''St. Austell: Church, Town, and Parish'', cites records which show a church was dedicated on 9 October 1262 by Bishop Bronescombe, and other records show a church there in 1169, dedicated to "Sanctus Austolus". The current church dates from the 13th–14th centuries, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineral Alteration
Mineral alteration refers to the various natural processes that alter a mineral's chemical composition or crystallography. Mineral alteration is essentially governed by the laws of thermodynamics related to energy conservation, relevant to environmental conditions, often in presence of catalysts, the most common and influential being water (H2O). The degree and scales of time in which different minerals alter vary depending on the initial product and its physical properties and susceptibility to alteration. Some minerals such as quartz and zircon are highly resistant to alteration under normal weathering conditions. Yet quartz may alter to stishovite with intense pressure, and zircon to ''cyrtolite'' (a metamict zircon) with amount of radioactive components and time. In some circumstances, a mineral alters while maintaining its outer form known as a pseudomorph. Mineral alteration is distinctly different than the rock alteration process metamorphism. It also differs from weathe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 scale of mineral hardness, based on scratch hardness comparison, defines value 4 as fluorite. Pure fluorite is colourless and transparent, both in visible and ultraviolet light, but impurities usually make it a colorful mineral and the stone has ornamental and lapidary uses. Industrially, fluorite is used as a flux for smelting, and in the production of certain glasses and enamels. The purest grades of fluorite are a source of fluoride for hydrofluoric acid manufacture, which is the intermediate source of most fluorine-containing fine chemicals. Optically clear transparent fluorite has anomalous partial dispersion, that is, its refractive index varies with the wavelength of light in a manner that differs from that of commonly used glasses, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 (). Kaolinite is a soft, earthy, usually white, mineral (dioctahedral phyllosilicate clay), produced by the chemical weathering of aluminium silicate minerals like feldspar. It has a low shrink–swell capacity and a low cation-exchange capacity (1–15 meq/100 g). Rocks that are rich in kaolinite, and halloysite, are known as kaolin () or china clay. In many parts of the world kaolin is colored pink-orange-red by iron oxide, giving it a distinct rust hue. Lower concentrations of iron oxide yield the white, yellow, or light orange colors of kaolin. Alternating lighter and darker layers are sometimes found, as at Providence Canyon State Park in Georgia, United States. Kaolin is an important raw material in many industries and app ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
