Certain minerals, such as uraninite, cannot form under significant exposure to oxygen.    From Wordnik.com.  [Luskin vs. Science (and Scientific American) - The Panda's Thumb] Reference

Pitchblende or uraninite is an intensely black mineral of a specific gravity of 9.5 and is found in commercial quantities in.    From Wordnik.com.  [Marvels of Modern Science] Reference

This led Davidson9 to conclude that the uraninite bearing rocks are not placer riverine deposits, as is suggested by Tamzek.    From Wordnik.com.  [Luskin vs. Science (and Scientific American) - The Panda's Thumb] Reference

He already knew ore -- the glossy, sub-metallic, pitchy black luster of uraninite or pitchblende; the yellows of autunite and carnotite; the variant and confusing greens of tobernite.    From Wordnik.com.  [First Lensman]

On page 17 Wells notes that uraninite deposits have been found in more recent rocks, but neglects to mention to his readers that these only occur under rapid-burial conditions, whereas ancient deposits of uraninite occur in slow deposition conditions, for example in sediments laid down by rivers, so that the minerals were exposed to atmospheric gases for significant periods of time before burial.    From Wordnik.com.  [Luskin vs. Science (and Scientific American) - The Panda's Thumb] Reference

Tamzek asserts that the mineral uraninite, present on the early Earth, cannot form under “significant exposure to oxygen”, however a recent publication from the Nasa Astrobiology Institute stated that its P.I. had observed the, “survival of uraninite … under an oxic atmosphere” and instability of uraninite under an oxygen-poor atmosphere, which was said to be “supporting … evidence for … an oxic Archaean atmosphere.”.    From Wordnik.com.  [Luskin vs. Science (and Scientific American) - The Panda's Thumb] Reference

Some researchers have found that the uranium conglomerates bearing uraninite have a texture and mineralogical makeup (uraninite, pyrite, molybdenite, and sulfides) one would expect if they were deposited by hydrothermal solutions, indicating that the uranium was deposited deep in the earth, far removed from the atmosphere, similar to what is observed happening in the origin of modern and more recently formed uraninite deposits9 (which obviously occurred in an oxygenic atmosphere).    From Wordnik.com.  [Luskin vs. Science (and Scientific American) - The Panda's Thumb] Reference

There were two other mines that produced the same uraninite ore as the one at which Hanlon was stationed.    From Wordnik.com.  [Man of Many Minds] Reference

Aside from silicate hosts (biotite and hornblende), uraninite is intergrown with pyrrhotite, molybdenite, and zircon.    From Wordnik.com.  [Digital50.com Digital 50 Daily Industry News RSS Feed] Reference

Several meter thick pegmatitic granite dykes hosting uraninite, uranophane and apatite were also observed by IOS geologists.    From Wordnik.com.  [Marketwire - Breaking News Releases] Reference

It occurs naturally in low concentrations in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite.    From Wordnik.com.  [Citizendium, the Citizens' Compendium - Recent changes [en]] Reference

The principal sources of uranium and radium are the minerals carnotite (hydrous potassium-uranium vanadate) and pitchblende or uraninite (uranium oxide).    From Wordnik.com.  [The Economic Aspect of Geology] Reference

Pitchblende, or uraninite, is an extremely radioactive mineral used as a major component for the production of fuel for nuclear power plants and nuclear arms.    From Wordnik.com.  [RIA Novosti] Reference

He was standing there, to all appearances strictly on the job of making his charges work, when Philander came crawling up the rise into the pocket where this crew was mining the glossy, lustrous pitch-blank uraninite ore.    From Wordnik.com.  [Man of Many Minds] Reference

7 Regardless, the origin of uraninite has also been a subject of controversy.    From Wordnik.com.  [Luskin vs. Science (and Scientific American) - The Panda's Thumb] Reference

Finally, Wells doesn’t mention to his readers that pyrite, a mineral even more vulnerable to oxidation than uraninite, is found unoxidized in pre-2.5 bya rocks, and with significant evidence of long surface exposure i.e. grains weathered by water erosion; e.g.    From Wordnik.com.  [Luskin vs. Science (and Scientific American) - The Panda's Thumb] Reference

"The March Fly mineralization appears to be uraninite, controlled by a specific association of structure and rock type.    From Wordnik.com.  [Marketwire - Breaking News Releases] Reference

It occurs in numerous minerals such as pitchblende, uraninite, carnotite, autunite, uranophane, and tobernite.    From Wordnik.com.  [Uranium] Reference