Geology stuff I didn't know

From Serendipity comes this nifty tidbit. The element Uranium degrades into Lead. Neat, huh? Also, I would love to get my hands on some of the green glass created by the first detonation of an atomic bomb on American soil. It would be an interesting addition to my collection of ugly rocks.
Here's an excerpt from the article:

" Most natural elements have very stable atoms which are impossible to split except by bombardment by particle accelerators. For all practical purposes, the one true element whose atoms can be split comparatively easily is the metal Uranium. Uranium's atoms are unusually large, henceforth, it is hard for them to hold together firmly. This makes Uranium-235 an exceptional candidate for nuclear fission.

Uranium is a heavy metal, heavier than gold, and not only does it have the largest atoms of any natural element, the atoms that comprise Uranium have far more neutrons than protons. This does not enhance their capacity to split, but it does have an important bearing on their capacity to facilitate an explosion.

There are two isotopes of Uranium. Natural Uranium consists mostly of isotope U-238, which has 92 protons and 146 neutrons (92+146=238). Mixed with this isotope, one will find a 0.6% accumulation of U-235, which has only 143 neutrons. This isotope, unlike U-238, has atoms that can be split, thus it is termed "fissionable" and useful in making atomic bombs. Being that U-238 is neutron-heavy, it reflects neutrons, rather than absorbing them like its brother isotope, U-235.
Both isotopes of Uranium are naturally radioactive. Their bulky atoms disintegrate over a period of time. Given enough time (over 100,000 years or more) Uranium will eventually lose so many particles that it will turn into the metal Lead."