Illite

Illite

Illite is a non-expanding, clay-sized, micaceous mineral. Illite is a phyllosilicate or layered alumino-silicate. Its structure is constituted by the repetition of Tetrahedron – Octahedron – Tetrahedron (TOT) layer. The interlayer space is mainly occupied by poorly hydrated potassium cations responsible for the absence of swelling. Structurally illite is quite similar to muscovite or sericite with slightly more silicon, magnesium, iron, and water and slightly less tetrahedral aluminium and interlayer potassium. The chemical formula is given as (K,H3O)(Al,Mg,Fe)2(Si,Al)4O10 [(OH)2,(H2O)] [ [http://webmineral.com/data/Illite.shtml Illite Mineral Data ] ] , but there is considerable ion substitution. It occurs as aggregates of small monoclinic grey to white crystals. Due to the small size, positive identification usually requires x-ray diffraction analysis. Illite occurs as an alteration product of muscovite and feldspar in weathering and hydrothermal environments. It is common in sediments, soils, and argillaceous sedimentary rocks as well as in some low grade metamorphic rocks. Glauconite in sediments can be differentiated by x-ray analysis.

The cation exchange capacity (CEC) of illite is smaller than that of smectite but higher than that of kaolinite, typically around 20 – 30 meq/100 g.

Illite was first described for occurrences in the Maquoketa shale in Calhoun County, Illinois, USA, in 1937. The name was derived from its type location in Illinois. Illite is also called hydromica or hydromuscovite. Brammallite is a sodium rich analogue.

Illite is also used in food supplements, with claimed benefits that range from bowel function to reduction of heavy metals in the blood. Apparently, a French company, Argiletz, provides a wide range of products which are offered for sale in the UK and elsewhere. "Green clay", a term used in several languages, often contains illite. In Scotland, internal uses of illite probably date back to Celtic times.

References

* [http://www.amazon.com/dp/0471463027/ Mitchell J.K. (1993)] Fundamentals of soil behavior. Second edition. John Wiley and Sons, Inc., New York. 437 pp, see Chapter 3, Soil Mineralogy, p. 32.

External links

* [http://webmineral.com/data/Illite.shtml Webmineral]
* [http://pubs.usgs.gov/of/of01-041/htmldocs/clays/illite.htm USGS]
* [http://www.mindat.org/min-2011.html Mindat]


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Look at other dictionaries:

  • Illite — Catégorie IX : silicates[1] Général Formule brute (K,H3O)(Al,Mg,Fe)2(Si,Al)4 …   Wikipédia en Français

  • illite — ● illite nom féminin (de Illinois, nom propre) Minéral argileux de structure et de composition proches de celles des micas, abondant dans les sols des régions tempérées. ● illite (synonymes) nom féminin (de Illinois, nom propre) Minéral argileux… …   Encyclopédie Universelle

  • illite — ☆ illite [il′īt΄ ] n. [< ILL(INOIS) + ITE1] any of a group of micalike clay minerals usually consisting of interlayered muscovite and montmorillonite …   English World dictionary

  • illite — illitic /i lit ik/, adj. /il uyt/, n. any of a group of clay minerals, hydrous potassium aluminosilicates, characterized by a three layer micalike structure and a gray, light green, or yellowish brown color. [1937; ILL(INOIS) + ITE1] * * * ▪… …   Universalium

  • illite — ilitas statusas T sritis chemija apibrėžtis Mineralas. formulė (K,H₃O)(Al,Mg,Fe)₂(SiAl)₄O₁₀[(OH)₂,H₂O] atitikmenys: angl. hydromuscovite; illite rus. гидромусковит; иллит ryšiai: sinonimas – hidromuskovitas …   Chemijos terminų aiškinamasis žodynas

  • illite — noun Etymology: Illinois, state of United States + 1 ite Date: 1937 any of a group of clay minerals having essentially the crystal structure of muscovite • illitic adjective …   New Collegiate Dictionary

  • illite — noun A micaceous phyllosilicate mineral with aggregates of grey or white monoclinic crystals. Syn: hydromica, hydromuscovite …   Wiktionary

  • illite —    A clay mineral …   Lexicon of Cave and Karst Terminology

  • illite — il·lite …   English syllables

  • illite — il•lite [[t]ˈɪl aɪt[/t]] n. mir any of a group of clay minerals, hydrous potassium aluminosilicates, characterized by a three layer micalike structure and a gray, light green, or yellowish brown color • Etymology: 1937; Ill(inois)+ ite I… …   From formal English to slang

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