uraninite

enUK

u·ra·ni·nite

U0142400 (yo͝o-rā′nə-nīt′)n. A complex brownish-black mineral, UO₂, forming the chief ore of uranium and containing variable amounts of radium, lead, thorium, and other elements. It is isomorphous with thorianite.

[German Uranin (from New Latin ūranium, uranium; see uranium) + -ite.]

uraninite

(jʊˈrænɪˌnaɪt) n (Minerals) a blackish heavy radioactive mineral consisting of uranium oxide in cubic crystalline form together with radium, lead, helium, etc: occurs in coarse granite. Formula: UO2[C19: see uranium, -in, -ite¹]

u•ran•i•nite

(yʊˈræn əˌnaɪt, -ˈreɪ nə-)

n. a radioactive mineral, uranium dioxide, UO₂, usu. found mixed with its decay products: the primary ore of uranium. [1875–80; uran (ium) + -in¹ + -ite¹]

Thesaurus

Noun

uraninite - a mineral consisting of uranium oxide and trace amounts of radium and thorium and polonium and lead and helium; uraninite in massive form is called pitchblende which is the chief uranium orepitchblendeatomic number 92, uranium, U - a heavy toxic silvery-white radioactive metallic element; occurs in many isotopes; used for nuclear fuels and nuclear weaponsuranium ore - any ore from which uranium can be extracted

uraninite

enUK

uraninite:

see pitchblendepitchblende
, dark, lustrous, heavy mineral, a source of radium and uranium. Largely natural uranium oxides, triuranium octaoxide (U₃O₈) and uranium dioxide (UO₂
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Uraninite

a mineral, an anhydrous oxide of uranium (U⁴⁺) with the idealized formula UO₂, which occurs only in synthetic materials. All natural uraninites contain UO₃ along with UO₂. The ratio of UO₂ to UO₃ is expressed by the value of the oxygen coefficient, which ranges from UO_2.17 to UO_2.92.

A distinction is made between uraninite proper, which occurs in the form of distinct crystals, pitchblende, which occurs in the form of cryptocrystalline collomorphic aggregates, and uranium oxides, which occur as friable earthy aggregates. Uraninite proper forms an isomorphic series with both thorianite, ThO₂, and yttrocerianite, (Y,Ce)O₂. In addition, all uraninites contain products of the radioactive decay of uranium and thorium: potassium, actinium, polonium, helium, lead, calcium, and zinc. Taking into account the most common admixtures, the formula for uraninite is (U⁴⁺ + U⁶⁺, Th, TR, Pb, Ca)O_1.9–2.5.

Uraninite crystallizes in the isometric system. The structure of ideal uraninite is similar to that of fluorite. The symmetry of the crystal lattice in natural uraninites is diminished owing to the intrusion of uranyl groups UO²⁺ into the structure, resulting in a primitive isometric structure. The most commonly encountered crystal shapes are cubes, octahedrons, and combinations thereof.

A brittle mineral, uraninite is of black color and has a pitchlike luster. It has a hardness of 5–6 on Mohs’ scale and a density of 8,000–10,000 kg/m³ (6,000–9,200 kg/m³ for pitchblende).

Uraninite proper is a high-temperature mineral typical of granitic and syenite pegmatites in association with complex niobates, tantalates, and titanates of uranium (samarskite, columbite, pyrochlore) and with zircon and monazite. It also occurs in hydro-thermal, skarn, and sedimentary deposits. Pitchblende, which is formed primarily in low-temperature hydrothermal and sedimentary deposits, occurs in association with sulfides, arsenides, native bismuth, arsenic, silver, and carbonates. The other uranium oxides are especially typical of hydrothermal sulfide-uranium and sedimentary deposits.

Uraninite is easily altered in the oxidation zone and serves as the initial material for the formation of the hydroxides, silicates, phosphates, and other minerals of U⁶⁺. All the varieties of uraninite are ores of uranium. There are large uraninite deposits in Canada, the United States, Africa, Australia, and France.

REFERENCE

Mineraly: Spravochnik, vol. 2, fasc. 2. Moscow, 1965.

L. N. BELOVA

uraninite

[′yu̇r·ə·nə‚nīt] (mineralogy) UO₂ A black, brownish-black, or dark-brown radioactive mineral that is isometric in crystallization; often contains impurities such as thorium, radium, cerium, and yttrium metals, and lead; the chief ore of uranium; hardness is 5.5-6 on Mohs scale, and specific gravity of pure UO₂ is 10.9, but that of most natural material is 9.7-7.5. Also known as coracite; ulrichite.

uraninite

u·ra·ni·nite

uraninite

u•ran•i•nite

uraninite

uraninite:

Uraninite

REFERENCE

uraninite

uraninite

Synonyms for uraninite

noun a mineral consisting of uranium oxide and trace amounts of radium and thorium and polonium and lead and helium

Synonyms

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