I bought an engagement ring August 15 2012. With on week the ring changed colors in a corner. So I took the ring back and they said they would fix it. I picked the ring back up September 11 and by September 18 the ring had the same problem. So again I took it back and went to pick it up October 17. When I went to pick up the ring this time the diamonds were dull and disgusting so I told the owner and he agreed and said he would send it back. Now I just want a refund but he says he can't give me one. Can I sue him for a full refund? And would I win?

I don't believe there is a lemon law on diamond rings. Also, the quality of a ring is subjective. So I don't think you can successfully sue for a refund. On the other hand, you can force them to provide the quality you paid for.