Depends... If you're in a bind for some quick cash then the pawn shop would be the way to go. They give you a ticket and hold your items for 90 days. This way, you would have enough time to resolve any money issues you may be experiencing and buy back your jewelry at the original price plus a little interest. However, if you just want to get rid of it becuase you no longer want it and will never wear it again, then sell it to a jewelry store or on Ebay.
The jewelry store would pay more, but you'd never see your jewelry again. They piece off the jewelry and make other items out of it, etc. The pawn shops are in business to make money off of your items, so they'll give you the least amount possible.