I have quite a few of these old open back settings, They are raw brass, and vintage. Very light weight, very detailed. American made. There is nothing wrong with these in fact they are very nice but the size is very unusual. Yes they made a few stones that size but not common. The edge is also very narrow so odds of glue bonding seems not great. I am unsure what my customers would use them for. They are quite decorative but you are going to have to be creative. Hence the price.
