Value of this ring?

I agree, I recently tried to sell some of my old jewelry to my well-kept jeweler and all I could get was scrap for any of it! And not much for the scrap, at that. I would guess you'd be lucky to get $25 for that nice ring.
 
Yes, there is no resale market for secondhand jewelry. It is such a scam when you are buying a diamond and they try to sell you on the investment value. NO jeweler will buy a diamond from you for its market value. There would be no reason for them to do it. They can just go pull another rock out of the vault. Never buy a diamond as an investment.