The Collaborative International Dictionary
Uraninite \U*ran"i*nite\, n. (Min.) A mineral consisting chiefly of uranium oxide with some lead, thorium, etc., occurring in black octahedrons, also in masses with a pitchlike luster; pitchblende.
Wiktionary
n. (context mineralogy English) Any of several brownish-black forms of uranium dioxide, uraniumoxygen2, (especially pitchblende) that is the chief ore of uranium; it is isomorphous with thorianite.
WordNet
n. 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 ore [syn: pitchblende]
Wikipedia
__NOTOC__ Uraninite, formerly pitchblende, is a radioactive, uranium-rich mineral and ore with a chemical composition that is largely UO, but due to oxidation the mineral typically contains variable proportions of UO. Additionally, due to radioactive decay, the ore also contains oxides of lead and trace amounts of helium. It may also contain thorium, and rare earth elements.
It used to be known as pitchblende (from pitch, because of its black color, and blende, a term used by German miners to denote minerals whose density suggested metal content, but whose exploitation, at the time they were named, was either unknown, impossible or not economically feasible). The mineral has been known at least since the 15th century from silver mines in the Ore Mountains, on the German/Czech border. The type locality is the historic mining and spa town known as Joachimsthal, the modern day Jáchymov, on the Czech side of the mountains, where F.E. Brückmann described the mineral in 1772. Pitchblende from the Johanngeorgenstadt deposit in Germany was used by M. Klaproth in 1789 to discover the element uranium.
All uraninite minerals contain a small amount of radium as a radioactive decay product of uranium. Marie Curie used pitchblende, processing tons of it herself, as the source material for her isolation of radium in 1898.
Uraninite also always contains small amounts of the lead isotopes Pb and Pb, the end products of the decay series of the uranium isotopes U and U respectively. Small amounts of helium are also present in uraninite as a result of alpha decay. Helium was first found on Earth in uraninite after having been discovered spectroscopically in the Sun's atmosphere. The extremely rare elements technetium and promethium can be found in uraninite in very small quantities (about 200 pg/kg and 4 fg/kg respectively), produced by the spontaneous fission of uranium-238.
Usage examples of "uraninite".
In the end, because we need the uraninite ore from the Belgian Congo, we decided we had to have him.
One of the very few known sources of uraninite ore, from which it was theoretically possible to extract uranium 235, was in Katanga Province of the Belgian Congo.
From Grunier it had been learned that there were in fact many tons of uraninite in Katanga Province lying around as by-products of other Union Mini re mining and smelting operations.
Donovan then sent an so a agent to the Belgian Congo from South Africa who had returned with fifty pounds of uraninite ore in twenty bags.
Seven more samples had not contained enough uraninite to make refining possible.
The few minutes it would take to tell the President how he planned to get the uraninite ore from the Belgian Congo would have to come from the total time Roosevelt was able to give him.
The Manhattan Project was intended, in the great secret of the Second World War, to refine the uraninite into uranium 235, and from the uranium 235 to construct a bomb, an "atomic bomb" that would have the explosive equivalent of twenty thousand tons of Roosevelt's, and Donovan's, great fear was that the Germans, among whose scientists were some of the greatest physicists in the world, and who were known to be conducting their own nuclear research, would learn of the American effort and increase their own research effort.
Some uraninite, hornblende, quartz-but a number of other compounds I cannot immediately identify.
He already knew ore -- the glossy, sub-metallic, pitchy black luster of uraninite or pitchblende.
He already knew ore—the glossy, sub-metallic, pitchy black luster of uraninite or pitchblende.