A girl? (you mentioned jewellery). I would agree, maybe a pair of real gold earrings or a pearl pendant, something like that. It would be something she'd have forever.
We asked our son what he wanted, offering things like a DSLR camera or a new ipad, but in the end he didn't want those things. He's really outdoorsy and likes hiking, etc, so we got him a large swiss army knife. It was $130CAD, so nowhere near the price of the items offered, but he loves it. The grin on his face was worth it.
So, get something she would really appreciate. It doesn't have to cost a fortune, just be something she might not buy for herself. Otherwise, money always works.