Last week, Marathon Fusion, a San Francisco-based energy startup, submitted a preprint detailing an action plan for synthesizing gold particles via nuclear transmutation—essentially the process of turning one element into another by tweaking its nucleus. The paper, which has yet to undergo peer review, argues that the proposed system would offer a new revenue stream from all the new gold being produced, in addition to other economic and technological benefits.
If you have a monopoly on the process, then its the same as the DeBeers Diamond Cartel. You can keep the price up by limiting the sale and spending a ton of money on marketing.