The heavy metal uranium is a lot less rare than you might think.
Natural uranium exists in the soil at a concentration of about four parts per million.
So on average, every truckload of dirt contains about one teaspoon of uranium. This makes uranium more abundant that gold or even silver. Natural uranium consists of three isotopes U234, U235 and U238 all of which are radioactive. Of the three, however, only U235 is fissile material that can power a nuclear reactor or nuclear weapon. That said, U235 constitutes only about 0.7 percent of natural uranium, with U238 and U234 making up the remaining 99.3 percent.