[vczf]

A layer of very thin gold can be transparent.

[digging]

I see, thanks for filling that in.

[wlesieutre]

Famously seen on the Apollo space suit sun visors. Their gold layer is thick enough to look gold, but thin enough that you can see through it:

http://heroicrelics.org/apollo-wwwttm/apollo-suit-a7l-leva-v...

http://heroicrelics.org/apollo-wwwttm/apollo-suit-a7l-leva-v...