[digging]

> Adding a thin coating of gold would not necessarily change that structure

My confusion is that I would normally expect a layer of gold not to permit any light to pass through. The underlying structure wouldn't be receiving any light, so there would be no photons to trap. Apparently a layer of gold can be applied thinly enough to transmit appreciable light, though.

[baruz]

Gold foil can be beaten to under 2 micrometers.

https://en.wikipedia.org/wiki/Gold_leaf