Uranium is the naturally occurring element with the highest atomic number. Its discovery in 1789 in the mineral pitchblende (or uraninite) is credited to the German chemist Martin Heinrich ...

Uranium (chemical symbol U) is a naturally occurring radioactive element. In its pure form it is a silver-coloured heavy metal, similar to lead, cadmium and tungsten. Like tungsten it is very dense, ...

Among the radioactive elements found and seized by police were depleted uranium, mercury, and the small plutonium sample.