Home > Uraninite
| Uraninite
|
| General
|
| Category | Mineral
|
| Chemical formula | uranum oxide , UO2
|
| 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, nitricProperties General Name Nitric acid Chemical formula H NO Appearance Clear or brown liquid Physical Formula weight 63. 0 amu Melting point 231 K (-42 °C) Boiling point 356 K (83 °C) Density 1. 5 ×103 kg/ m3 Solubility miscible Thermochemistry ΔH0 -1, and hydrofluoric acidGeneral Name Hydrogen fluoride Chemical formula H F Appearance Colorless gas Physical properties Formula weight 20. 1 amu Melting point 190 K (-83 °C) Boiling point 294 K (19. 5 °C) Density 0. 97 ×103 kg/ m3 (liquid) Solubility miscible with water Thermocs.
|
| Major varieties
|
| Pitchblende | Massive
|
Uraninite is a uraniumUranium is a chemical element in the periodic table that has the symbol U and atomic number 92. A heavy, silvery-white, toxic, metallic , and naturally- radioactive element, uranium belongs to the actinide series and its isotope uranium-235 is used as the-rich mineral with a composition that is largely UO2, but which also contains UO3 and oxideAn oxide is a chemical compound of oxygen with other chemical elements, e. rust ( iron oxide) or bauxite ( aluminium oxide). Oxides are extremely common in Earth's crust, and indeed in solid matter throughout the universe. Oxides are usually created throus of leadFor the "lead" in news writing, see news style. Lead is a chemical element in the periodic table that has the symbol Pb ( L. Plumbum and atomic number 82. A soft, heavy, toxic and malleable poor metal, lead has a dull gray appearance and is bluish white w, thoriumThorium is a chemical element in the periodic table that has the symbol Th and atomic number 90. Notable characteristics Thorium is a naturally occurring, slightly radioactive metal. When pure, thorium is a silvery white metal that retains its lustre for, and rare earthA rare earth is an oxide of a rare earth element. Often rare earth elements themselves are loosely called "rare earths". Rare earth elements, or metals, are the lanthanides and actinides. They come from the f-block. They are: lanthanum, cerium, praseodymis. It is most commonly known in the variety pitchblende. All uraninite minerals contain a small amount of radium 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.
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. It also occurs in Germany, England, and South Africa, and in New Hampshire, Connecticut, North Carolina, Wyoming, and New Mexico in the United States.
