According to Wikipedia, "some granites" contain 10 to 20 ppm of uranium, and the density of granite is about 2.65 g/cm^3. If a rocket contains 10t of pure uran

According to Wikipedia, "some granites" contain 10 to 20 ppm of uranium, and the density of granite is about 2.65 g/cm^3. If a rocket contains 10t of pure uranium, that is the same amount of uranium in a cube made of uranium-rich (20 ppm) granite, each side about 57m long. Now imagine how many such cubes would fit inside your favorite mountain.