Uranium is a rare element of rather high atomic weight. There are two different isotopes, one of them is even rarer and not stable. This U-257 is used to fuel atomic reactors and build atomic bombs.
Uranium forms minerals and ores. The minerals are generally exceptional, as they shine in strange colours under ultraviolet light. And they are not really healthy, as they emit a small but continuous radiation. Uranium is used for colour, and for ceramics, as is makes dark colours very good. Again the use is not a good idea, because of the radiation.
Uranium is mined all over the world. It is rather common, but mining is generally difficult and the amount of uranium is low. However, the amount of energy it may produce is enormous and the production of weapons does not follow economic rules.