You should take it to your local jewelers and antique stores, ask everyone and try and get an average. There are plenty of places on the net that will do evaluations for you too. After you’ve done this, set up an auction on an online auction house, or try and find one in town that is successful. If you’re looking for a certain amount of money then simply put a reserve on it, if someone wants your ring, they’ll pay it. I do know these things, my dad is an antique dealer lol.