Uraninite

- align=center bgcolor="#9966FF"	Uraninite		- align=center	- align=center bgcolor="#9966FF"	General		-	Category	Mineral	-	Chemical formula	uranium oxide, UO₂	- align="center" bgcolor="#9966FF"	Identification		-	Colour	Black or brownish	-	Crystal habit	Massive, botryoidal, granular. Crystals uncommon.	-	Crystal system	Isometric	-	Cleavage	Indistinct	-	Fracture	Conchoidal to uneven	-	Mohs Scale hardness	5 - 6	-	Luster	Submetallic, greasy	-	Refractive index	Opaque	-	Pleochroism	None	-	Streak	Same as colour, black or brownish	-	Specific gravity	7.5 - 10	-	Fusibility	?	-	Solubility	Soluble in sulfuric, nitric, and hydrofluoric acids.	- align="center" bgcolor="#9966FF"	Major varieties		-	Pitchblende	Massive	-

For the band, see Pitchblende (band).

Uraninite is a uranium-rich mineral with a composition that is largely UO₂ (uranium dioxide), but which also contains UO₃ and oxides of lead, thorium, and rare earths. It is most commonly known in the variety pitchblende. All uraninite minerals contain a small amount of radium as a radioactive decay product of uranium; it was in pitchblende from the Jáchymov in Czechoslovakia that Marie Curie discovered radium. Uraninite also always contains small amounts of the lead isotopes, Pb-206 and Pb-207, the end products of the decay series of the uranium isotopes U-238 and U-235 respectively. Small amounts of helium are also present in uraninite as a result of alpha decay. Helium was first discovered on Earth in uraninite after previously being discovered spectroscopically in the Sun's atmosphere. The extremely rare element technetium can be found in uraninite in very small quantities (about 0.2 ng/kg), produced by the spontaneous fission of uranium-238.

Uraninite is a major ore of uranium. An important occurrence of pitchblende is at Great Bear Lake in the Northwest Territories of Canada, where it is found in large quantities associated with silver. Some of the highest grade uranium occurrences in the world occur in the Athabasca Basin in northern Saskatchewan. It also occurs in Australia, Germany, England, and South Africa, and in New Hampshire, Connecticut, North Carolina, Wyoming, Colorado and New Mexico in the United States.

Reference

Dana's Manual of Mineralogy ISBN 0471032883

External links

Uranium minerals | Oxide minerals

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Reference

See also

External links