Any necklace setting and gem will work, so long as they are the same material.  This power source, however, is what will bring the magic back to the necklace... I hope.$B$BI'll gladly supply the gems needed for your version of the necklace, so long as the power source actually works.$B$BHead to Orgrimmar and keep your end of the bargain with Droffers and Son Salvage.  Just keep your mouth shut about our deal, and when you get back I might have a wonderful surprise for you.