Recently I have been trying to find out more about the process that is used to coat glasses lenses with gold. I asked about it in another forum last night and I was directed here. I initially thought that I could use the same process that NASA used to coat astronaut's helmet visors in gold, but now that is too expensive of a process. I want a thin transparent layer of gold on my glasses (lenses) basically. I have access to jewelry equipment.
You will have to use vapor deposition under high vacuum. This requires a piston vacuum pump to get a rough vacuum, then a turbomolecular or diffusion pump to get to high vacuum. Then heat gold in this vacuum till it melts. Gold vapor will deposit a thin layer on all surfaces of the container including your glasses.
While possible, it is not easy and it will probably cost less to get it done professionally by an optical coatings company than the gold you will waste in your attempts.