If you could somehow create a cheap and powerful particle accelerator, gold could concievably be produced in macroscopic amounts by irradiating mercury-198 (10%

If you could somehow create a cheap and powerful particle accelerator, gold could concievably be produced in macroscopic amounts by irradiating mercury-198 (10% by mass in naturally occuring mercury) with 6.8MeV gamma rays. There are other ways of doing it, but economics and practicality needs to be considered. It is probably easier to build a badass particle accelerator than a nuclear reactor. I am reasonably sure that most modern accelerator laboratories have done this experiment, but it is probably not economical with today's accelerators. (And imagine the capital costs!) This seems a very lucrative target for aspiring physicists. At a point in time this will probably become practical, but there will only be a small window in which it is economical to do so: once it becomes possible to perform large-scale nuclear gold transmutation, gold prices will plummet due to excessive supply.