Can nanotechnology be used to change lead into gold?
No. Nanotechnology operates at the level of the atom, and gold atoms differ from lead atoms at the subatomic level. To transmute atoms of one element into atoms of another element is possible only by interfering with the forces which bind the atom’s parts protons, neutrons, and electrons together. So far as is known, this is beyond the capability of nanotechnology to achieve directly. Nanotechnology can quite easily be used to turn coal into diamonds, however because both diamonds and coal are composed of carbon atoms; whether the atoms form diamonds or coal depends solely upon their arrangement. The irony of this is that diamonds will become relatively worthless as gemstones.
