Can anyone guess what the stone in this is?

[jewl]

 

[Avondale]

Just by this single picture? No. Could be an emerald, could be a piece of glass or plastic.

If you share more details about the ring, people here could give you some more ideas. But I would say don’t get your hopes up. Pieces without any identification or information about them are usually so because they don’t have a significant monetary value.

 

[jewl]

Thanks for your reply. I am guessing it’s not an emerald but that’s just me. The gold band seems to be 9k. On the inside it’s got S.G.W stamped on the inside. And something that looks like a boat.

 

[seaurchin]

I'd definitely expect the stone to be synthetic. A 9 karat setting would be relatively inexpensive so I wouldn't expect a very expensive stone to be set in it. The only way to absolutely know for sure would be to get it tested by a trusted lab but personally I don't think it would be worth the cost. It's a pretty ring though.

 

[Autumn in New England]

Welcome to the forum, jewl! Ditto everyone else's comments. Good luck... pretty piece.