Well they aren't smart criminals. And jewellers seldom melt down fine jewelry before trying to sell it as they can make more with it whole than. I made nearly a $200 profit on a silver necklace. There was a second hand store in town that was failing miserably because none wanted what they had and they rarely got new inventory. As they were going out of business they had an everything 50% of sale. I bought a silver herring bone necklace marked at $60 I assumed that was the discounted price which still seemed fair. I ended up paying $30 for it and was going to give it to my girlfriend at the time for her birthday. Well we split and I took it to a jeweler to see what I could get for it. I expected around what I paid for it honestly. As it was fairly small and could use a good cleaning and polishing. He offered me $225 because it has no broker or bent links. I took the money and never looked back. Now I coarsely search thrift stores for these hidden gems that could possibly turn a profit.