Thank for your feedback. The value is based on the quality of the work. Of course there are cheaper ones but they are mechanically reproduced. There are also much more expensive cammeo on the market. The framing is for sure 18 k gold. In case of doubt, anybody can check it and sent it back to me if I not convinced. I am sure we can organize a longer escrow service.
Regarding the quantity of gold, may be I have not understood the question.
Jewel are consumer good, they are not considered an investment, for that you have to buy gold bullions. The difference with other consumer goods such as a phone is that a phone has no value after two years, a jewel preserves his value in the long period. Of course a phone and a cammeo are two different things, there are people that prefer one to the other and other people that have both...
Definitely not arguing with the fact that some cameo brooches are cheap - some are ludicrously expensive depending on the quality.
As for the gold, I was just pointing out that the amount is insignificant, and doesn't really add to the value of this as much as other items of jewellery. This would have at most 2 grams of 18ct Gold, which is about ~$60 worth. The cameo itself is what would make this valuable, should it be a quality piece.
Again, I think this is entirely the wrong place to try and sell this. You would get a buyer for this easily on eBay. On a Bitcoin Forum? Not so sure. Good luck anyway