Thorite

Thorite

Thorite, (Th,U)SiO4, is a rare nesosilicate of thorium that crystallizes in the tetragonal system and is isomorphous with zircon. It is the most common mineral of thorium and is nearly always strongly radioactive. It was named in 1829 to reflect its thorium content.

Specimens of thorite generally come from igneous pegmatites and volcanic extrusive rocks, hydrothermal veins and contact metamorphic rocks. It is also known to occur as small grains in detrital sands. Crystals are rare, but when found can produce nicely shaped short prismatic crystals with pyramidal terminations.

Thorite is currently an important ore of uranium. A variety of thorite, often called "uranothorite", is particularly rich in uranium and has been a viable uranium ore at Bancroft in Ontario, Canada. Other varieties of thorite include "orangite", an orange variety, and "calciothorite", an impure variety with trace amounts of calcium.

Thorite is commonly metamict and hydrated, making it optically isotropic and amorphous. Owing to differences in composition, the specific gravity varies from 4.4 to 6.6 g/cm3. Hardness is 4.5 and the luster is vitreous or resinous. The color is normally black, but also brownish black, orange, yellowish-orange and dark green.

Because thorite is highly radioactive, specimens are often "metamict". This is a condition found in radioactive minerals that results from the destructive effects of its own radiation on its crystal lattice. The effect can destroy a crystal lattice completely while leaving the outward appearance unchanged.

References

* [http://webmineral.com/data/Thorite.shtml Webmineral data]
* [http://www.mindat.org/min-3946.html Mindat.org]


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  • thorite — [ tɔrit ] n. f. • 1838; de thorium ♦ Minér. Silicate naturel de thorium (ThSiO4), brun orange. ● thorite nom féminin Silicate naturel de thorium, de formule ThSiO4, quadratique. ● thorite (synonymes) nom féminin Silicate naturel de thorium, de… …   Encyclopédie Universelle

  • Thorite — Tho rite, n. [So called by Berzelius from the Scandinavian god Thor. See {Thor}.] (Min.) A mineral of a brown to black color, or, as in the variety orangite, orange yellow. It is essentially a silicate of thorium. [1913 Webster] …   The Collaborative International Dictionary of English

  • thorite — [thôr′īt΄] n. [Swed thorit: see THORIUM & ITE1] a rare, usually dark, hard, radioactive mineral, thorium silicate, ThSiO4, that is usually hydrated …   English World dictionary

  • thorite — /thawr uyt, thohr /, n. a rare mineral, thorium silicate, ThSiO4, occurring in the form of yellow or black crystals. [1825 35; thor (as in THORIA, THORIUM) + ITE1, modeled on Sw thorit] * * * ▪ mineral       thorium silicate, ThSiO4, one of the… …   Universalium

  • thorite — toritas statusas T sritis chemija apibrėžtis Mineralas. formulė ThSiO₄ atitikmenys: angl. thorite rus. торит …   Chemijos terminų aiškinamasis žodynas

  • thorite — noun Etymology: Swedish thorit, from New Latin thorium Date: 1832 a rare mineral that is a brown to black or sometimes orange yellow silicate of thorium resembling zircon …   New Collegiate Dictionary

  • thorite — noun A radioactive mineral, composed mostly of thorium silicate (ThSiO), along with silicates of uranium and the rare earths …   Wiktionary

  • thorite — (to ri t ) s. f. Minéral trouvé en Norwége, près Brevig, sur l île de Loeven ; on en extrait le thorium …   Dictionnaire de la Langue Française d'Émile Littré

  • thorite — tho·rite …   English syllables

  • thorite — tho•rite [[t]ˈθɔr aɪt, ˈθoʊr [/t]] n. mir a rare radioactive mineral ore, thorium silicate, ThSiO4, occurring as grains and crystals • Etymology: < Sw thorit (1829); see thorium, ite I …   From formal English to slang

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