Kaolinite
General
Category	Mineral
Chemical formula	Al2Si2O5(OH)4
Identification
Color	White, sometimes red, blue or brown tints from impurities
Crystal habit	Earthy
Crystal system	triclinic
Cleavage	perfect on {001}
Fracture	Perfect
Mohs Scale hardness	2 - 2. A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes In Mineralogy, shape and size give rise to descriptive terms applied to the typical appearance or habit of Crystals The many terms used by mineralogists A crystal system is a category of Space groups which characterize Symmetry of structures in three dimensions with Translational symmetry in three directions In Crystallography, the triclinic Crystal system is one of the 7 lattice Point groups A crystal system is described by three basis vectors Cleavage, in Mineralogy, is the tendency of crystalline materials to split along definite planes creating smooth surfaces of which there are several named types In the field of Mineralogy, fracture is a term used to describe the shape and texture of the surface formed when a Mineral is broken The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material 5
Luster	dull and earthy
Refractive index	α 1. Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium 553 - 1. 565, β 1. 559 - 1. 569, γ 1. 569 - 1. 570
Streak	white
Specific gravity	2. The streak (also called powder color) of a Mineral is the Color of the powder produced when it is dragged across an unweathered surface Specific gravity is defined as the ratio of the Density of a given solid or liquid substance to the density of water at a specific temperature and pressure typically 16 - 2. 68
References	[1][2]

Kaolinite is a clay mineral with the chemical composition Al₂Si₂O₅(OH)₄. Clay minerals are hydrous Aluminium phyllosilicates, sometimes with variable amounts of Iron, Magnesium, Alkali metals Alkaline WikipediaNaming Silicon (ˈsɪlɪkən or /ˈsɪlɪkɒn/ silicium is the Chemical element that has the symbol Si and Atomic number 14 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the In Chemistry, hydroxide is the most common name for the diatomic Anion OH− consisting of Oxygen and Hydrogen It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedra (Deer et al. The silicate minerals make up the largest and most important class of rock-forming Minerals They are classified based on the structure of their silicate Ion group A tetrahedron (plural tetrahedra) is a Polyhedron composed of four triangular faces three of which meet at each vertex. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny An octahedron (plural octahedra is a Polyhedron with eight faces , 1992). Rocks that are rich in kaolinite are known as china clay or kaolin.

The name is derived from Gaolin 高岭 ("High Hill") in Jingdezhen, Jiangxi province, China. Jingdezhen ( Wade-Giles: Ching-te-chen or the Town of Jingde, is a Prefecture-level city, previously a town, in Jiangxi Province ( Postal map spelling: Kiangsi is a southern province of the People's Republic of China, spanning from the banks of the Yangtze River China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National Kaolinite was first described as a mineral species in 1867 for an occurrence in the Jari River basin of Brazil. The Jari River, is a northern tributary of the Amazon river on the border between the states of Pará and Amapá in northeastern Brazil |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld ^[3]

Kaolinite is one of the most common minerals; it is mined, as kaolin, in Brazil, France, United Kingdom, Germany, India, Australia, Korea , the People's Republic of China, and the USA. |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld This article is about the country For a topic outline on this subject see List of basic France topics. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country For a topic outline on this subject see List of basic Australia topics. Korea is a geographic area composed of two sovereign countries a civilization and a former state situated on the Korean Peninsula in East Asia. Talk People's Republic of China) PEOPLE'S REPUBLIC OF CHINA ARTICLE GUIDELINES The United States of America —commonly referred to as the

Kaolinite has a low shrink-swell capacity and a low cation exchange capacity (1-15 meq/100g. In Soil science, cation exchange capacity (CEC is the capacity of a Soil for Ion exchange of positively charged ions between the soil and the ) It is a soft, earthy, usually white mineral (dioctahedral phyllosilicate clay), produced by the chemical weathering of aluminium silicate minerals like feldspar. Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and WikipediaNaming For the Artificial intelligence Androids of the 1990s Science fiction series Space Above and Beyond, see Silicate (AI Feldspar is the name of a group of rock-forming Minerals which make up as much as 60% of the Earth 's crust. In many parts of the world, it is colored pink-orange-red by iron oxide, giving it a distinct rust hue. Altogether there are sixteen known Iron Oxides and oxyhydroxides Rust is a general term for a series of Iron oxides, usually red oxides formed by the reaction of Iron with Oxygen in the presence of water or air Lighter concentrations yield white, yellow or light orange colours. Alternating layers are sometimes found, as at Providence Canyon State Park in Georgia, USA. Providence Canyon State Park is a 1003 Acre (406 km2) State park located in Stewart County in west central Georgia. The State of Georgia ( is a state in the United States and was one of the original Thirteen Colonies that revolted against British rule The United States of America —commonly referred to as the

A kaolin mine in Ruse Province, Bulgaria

Predominance in tropical soils

Kaolinite clay occurs in abundance in soils that have formed from the chemical weathering of rocks in hot, moist climates - for example in tropical rainforest areas. Rousse (or Ruse Province (Русенска област is a province in northern Bulgaria, neighbouring Romania via the Danube. The state of Bulgaria (България transliterated bg-Latn ''Balgaria'' The country preserves the traditions (in ethnic name language and alphabet of the First Bulgarian Comparing soils along a gradient towards progressively cooler or drier climates, the proportion of kaolonite decreases, while the proportion of other clay minerals such as illite (in cooler climates) or smectite (in drier climates) increases. Such climatically-related differences in clay mineral content are often used to infer changes in climates in the geological past, where ancient soils have been buried and preserved.

Structural transformations

Kaolin-type clays undergo a series of phase transformations upon thermal treatment in air at atmospheric pressure. Endothermic dehydroxylation (or alternatively, dehydration) begins at 550-600 °C to produce disordered metakaolin, Al₂Si₂O₇, but continuous hydroxyl loss (-OH) is observed up to 900 °C and has been attributed to gradual oxolation of the metakaolin (Bellotto et al. , 1995). Due to historic disagreement concerning the nature of the metakaolin phase, extensive research has led to general consensus that metakaolin is not a simple mixture of amorphous silica (SiO₂) and alumina (Al₂O₃), but rather a complex amorphous structure that retains some longer-range order (but not strictly crystalline) due to stacking of its hexagonal layers (Bellotto et al. , 1995).

2 Al₂Si₂O₅(OH)₄ —> 2 Al₂Si₂O₇ + 4 H₂O

Further heating to 925-950 °C converts metakaolin to a defect aluminum-silicon spinel, Si₃Al₄O₁₂, which is sometimes also referred to as a gamma-alumina type structure:

2 Al₂Si₂O₇ —> Si₃Al₄O₁₂ + SiO₂

Upon calcination to ~1050 °C, the spinel phase (Si₃Al₄O₁₂) nucleates and transforms to mullite, 3 Al₂O₃ · 2 SiO₂, and highly crystalline cristobalite, SiO₂:

3 Si₃Al₄O₁₂ —> 2 Si₂Al₆O₁₃ + 5 SiO₂

Uses

Kaolin is used in ceramics, medicine, coated paper, as a food additive, in toothpaste, as a light diffusing material in white incandescent light bulbs, and in cosmetics. The word ceramic is derived from the Greek word κεραμικός ( keramikos) Medicine is the art and science of healing It encompasses a range of Health care practices evolved to maintain and restore Human Health by the Coated paper is Paper which has been coated by a compound to impart certain qualities to the paper including weight and surface gloss smoothness or ink absorbency Food additives are substances added to food to preserve flavour or improve its taste and appearance Toothpaste is a Paste or Gel Dentifrice used to clean and maintain the aesthetics and health of Teeth. A lamp is a replaceable component such as an Incandescent light bulb, which is designed to produce Light from Electricity. It is also used in most paints and inks. The largest use is in the production of paper, including ensuring the gloss on some grades of paper. Commercial grades of kaolin are supplied and transported as dry powder, semi-dry noodle or as liquid slurry.

A more recent, and more limited, use is as a specially formulated spray applied to fruits, vegetables, and other vegetation to repel or deter insect damage. Kaolin Sprays are an insect barrier applied to Orchard and field Plants to exclude pests The term " vegetable " generally means the edible parts of Plants The definition of the word is traditional rather than Scientific, however The codling moth ( Cydia pomonella) is a member of the Lepidopteran family Tortricidae. A traditional use is to soothe an upset stomach, similar to the way parrots (and later, humans) in South America originally used it. In Human anatomy, the stomach is a J-shaped hollow muscular organ of the Gastrointestinal tract involved in the second phase of Digestion, following Parrots are birds of the roughly 350 Species in 85 genera comprising the order Psittaciformes, found in most warm and tropical regions South America is a Continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a ^[4] Until the early 1990s it was the active substance of anti-diarrhea medicine Kaopectate. Kaopectate, known medically as Bismuth subsalicylate, is an orally taken Medication from Chattem

In April of 2008, the Naval Medical Research Center announced the successful use of a Kaolinite-derived aluminosilicate nanoparticles infusion in traditional gauze known commercially as QuikClot® Combat Gauze. Aluminosilicate Minerals are minerals composed of Aluminium, Silicon, and oxygen In Nanotechnology, a particle is defined as a small object that behaves as a whole unit in terms of its transport and properties Gauze is a thin Translucent fabric with a loose open Weave. Its name may derive etymologically from the Persian word for ^{[5] [6]}.

Miscellany

The crystallography of kaolinite played a role in Linus Pauling's work on the nature of the chemical bond. Crystallography is the experimental science of determining the arrangement of Atoms in Solids In older usage it is the scientific study of Crystals The Linus Carl Pauling (February 28 1901 – August 19 1994 was an American Scientist, Peace activist, Author and educator. A chemical bond is the physical process responsible for the attractive interactions between Atoms and Molecules and which confers stability to diatomic and polyatomic

The Eden Project

Kaolinite can contain very small traces of uranium and thorium, and is therefore useful in radiological dating. Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the Thorium (ˈθɔːriəm is a Chemical element with the symbol Th and Atomic number 90 Radiometric dating (often called radioactive dating) is a technique used to date materials usually based on a comparison between the observed abundance of a naturally occurring While a single magazine made using kaolin does not contain enough radioactive material to be detected by a security-oriented monitor, this does result in truckloads of high end glossy paper occasionally tripping an overly-sensitive radiation monitor. Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. Radiation dosimetry is the calculation of the Absorbed dose in matter and tissue resulting from the exposure to Ionizing radiation.

The Eden Project, a large environmental complex near St Austell, Cornwall, England, is constructed in a disused china clay pit. The Eden Project is a visitor attraction including the world's largest greenhouse An ecosystem is a natural unit consisting of all plants animals and micro-organisms( Biotic factors in an area functioning together with all of the non-living physical ( St Austell (Sen Ostell is a town in Cornwall, England, UK. St Austell has a population of 22658 (according to the 2001 census Cornwall ( Kernow ˈkɛɹnɔʊ is the most southwesterly county of England, on the Peninsula that lies to the west of the River Tamar England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland

Sandersville, a small town in Georgia, USA, holds an annual kaolin festival every year. Sandersville is a city in Washington County, Georgia, United States. Sandersville has huge kaolin deposits throughout the town and the surrounding areas. The town is based on the kaolin industry.

Kaolin. (unknown scale)

When heated to between 650°C and 900°C kaolinite dehydroxylates to form Metakaolin. According to the American [National Precast Concrete Association] this is a supplementary cementitious material (SCM), when added to a concrete mix Metakaolin affects the acceleration of Portland cement hydration when replacing Portland cement by 20 percent by weight.

See also

• Dickite
• Geology of Cornwall
• Halloysite
• Nacrite
• List of minerals
• Porcelain
• Paper
• Clay pit
• Kaolin Deposits of Charentes Basin, France

Footnotes

References

• Deer, W. A. , Howie, R. A. , and Zussman, J. (1992) An introduction to the rock-forming minerals (2nd ed. ). Harlow: Longman ISBN 0-582-30094-0.
• Hurlbut, Cornelius S. , Klein, Cornelis (1985) Manual of Mineralogy - after J. D. Dana, 20th ed. , Wiley, pp. 428 - 429, ISBN 0-471-80580-7.
• Breck, D. W. (1984)Zeolite Molecular Sieves, Robert E. Brieger Publishing Company: Malabar, FL, pp. 314-315, ISBN 0-89874-648-5.
• Bellotto, M. , Gualtieri, A. , Artioli, G. , and Clark, S. M. (1995) Kinetic study of the kaolinite-mullite reaction sequence. Part I: kaolinite dehydroxylation', Phys. Chem. Minerals, Vol 22, 207-214.
• The Mineral KAOLINITE - Mineral Galleries
• MSDS: Incandescent Light Bulb - GE

External links

• China Clay Museum