Wouldn't it be great if you could just create gold and precious stones? Think about it, you could make food too! All you need to do is get the carbon formula right and then you can create anything you want, in any amount you want.
But maybe it is harder than simply saying you are going to. Maybe you actually need to use carbon to mak carbbon?
To create carbon we can add four electrons to an atom of air. That said the electrical addition to the atoms in the air will produce carbon. Carbon is usually organic, so to create gold we need to take a big rock and tthen charge it with electrons, like electrocuting the rock, so to speak. The thing is the rock is non metallic, so, we could simply make it a conductor by bombarding it with protons from one side, and electrons from the other side. It might explode, so it will be a good idea to use the gamma rays from a laser to expose the rock to gamma correction, where the first gamma rays fall away at the surface, the second also do, but the third wave of rays will penetrate the rock. Load these rays with attached electrons or protons and neutrons respectively, and you can do a lot with a rock!
To make something like food, all you need to do is use some moisture for the rays to fall onto. This will typically produce some scum or algae or something, but you can alske it tuned to produce food. Stick this on a conveyor belt and you have a end to world hunger!