I worked at a lab for a while that had a atomic layer deposition setup for gold. I believe they charged a modest amount (a few cents? a few dollars?) per single

I worked at a lab for a while that had a atomic layer deposition setup for gold. I believe they charged a modest amount (a few cents? a few dollars?) per single-atom layer of gold. The device had a bell-shaped chamber that you would place your wafer into, but of course no matter how big or small the wafer was, the entire interior of the chamber got an even coating of gold. The technician who operated it had a ring he would put inside the chamber alongside his own samples, so over the course of several years he had gradually accumulated enough layers to "turn it into gold."