Nuclear transmutation is magic, according to Larry Niven's definition of magic. It is also a prerequisite of cheap, cheap construction.

It works like this:

1. Locate a plentiful and cheap material. Hydrogen, for instance, would be good, although pretty much anything can be used.

2. Place it in a nuclear transmutator. This is a black box which breaks things down/build them up. It does this by breaking down the atoms it contains into a sort of plasma of disassociated electrons, neutrons, and protons. These can then be reassembled as desired.

3. Just Add Water. This is not, strictly speaking, untrue - water adds oxygen and hydrogen to the mix, and these can then be broken down into their constituent particles.

4. Remove your gold, ionized plutonium, or other useful substance.

If you find any inaccuracies, please /msg me.