How is Uranium found in nature?
Uranium is not a rare element in nature. It averages about 2-4 ppm in the earth’s crust, which means it is more abundant than silver, tin, and zinc. In general, uranium tends to concentrate in felsic igneous rocks, and is noticeably depleted in most mafic rocks. Uranium is soluble and is easily transported by ground waters, and therefore uranium concentrations in bogs and reduced alluvium are not unusual. Uranium is found in trace amounts in the oceans and in human bodies (especially finger nails) but it is not found in the atmosphere. Uranium does not occur in nature as a native element, except in solution. Owing in part to the two common valences of uranium (IV and VI) there are dozens of uranium minerals including uraninite, uranothorite, carnotite, autunite, thucolite, coffinite, and uranophane. The world’s biggest producer of uranium is Canada, with mines in Saskatchewan, which produces about 1/3 of the world’s uranium. Other uranium producing countries are Australia, Niger, Namib
