HI,
as far as I know, in general teh mount of a jewel is an indication of quality. E.g. a gold ring with a stone in it is an indication that the stone is gold worth. Nobody would mount a diamond in a silver or metal ring and vice versa.
As far concerns ebay you are right. The best place to sell things remains the traditional ones. As I´m - as the most of us I suppose - enthusiastic of bitcoin I did this attempt. From my experience I have to say that probably bitcoin are still not used as alternative to money but they are still an investment like gold or stocks.

I have a friend owning web site selling organic food. I convinced him to accept bitcoin. Let's see if there is a reaction of the market in this other area.