It occurs as an alteration product of uraninite and primary selenium-bearing sulfides, such as penroseite.
12.
They extracted the radium compound from uraninite and published the discovery at the French Academy of Sciences five days later.
13.
Although uraninite-bearing granite pegmatites are common, clarkeite is rare and occurs intimately intergrown with other uranium minerals.
14.
It is especially closely associated with torbernite, but is also found amongside autunite, meta-autunite and uraninite.
15.
They could be a defining constituent, such as uranium in uraninite, autunite, and carnotite, or as trace impurities.
16.
It is found in many minerals including uraninite ( most common uranium ore ), autunite, uranophane, torbernite, and coffinite.
17.
In nature, radium is found in uranium ores in trace amounts as small as a seventh of a gram per ton of uraninite.
18.
Primary ore minerals are uraninite and pitchblende, which occur as cavity fills and coatings on quartz grains within permeable sandstone breccias within the pipe.
19.
It occurs associated with opal, chalcedony, calcite, gypsum, fluorite, uraninite, thorogummite, uranophane, boltwoodite, carnotite and margaritasite.
20.
Helium was first found on Earth in uraninite after having been discovered fg / kg respectively ), produced by the spontaneous fission of uranium-238.
