So pretty please see last photo on the back where cabochon is there’s a little bit of what looks like toothpaste residue that was used to polish this piece and the person didn’t remove all of the toothpaste I just let it be it isn’t hurting anything you can’t tell from front should come out easy the pin has lots of patina which I think it makes it even more lovely. Bezel set glass? Or stone? I’m not sure which probably glass but like I said I don’t really know. It is also signed by maker and marked sterling measurements are shown in the above photo. Lovely little pin it will come with patina on pieces like this I tend to leave be and let future buyer decide on whether to polish I believe it is signed S.W. See photos above