well i think the first thing u want to know is be prepared to be disappointed. jewellery is worth less than half of what u bought it for. unless its from an ultra exclusive collection/ designer and it is limited in availability, then it wont be worth much at all.
take for instance diamonds, anyone that knows anything about the debeers cartel knows that diamonds are pretty much worthless as an investment vehicle.
i guess it depends on what u want from it, if u just want to move it along, then pawning it will get u some cash, but it wont realise the highest return. perhaps selling it through an enthusiast forum or seeing if any of the diamond/ gold traders might want it
can i ask what it is?