Just by the prongs and setting of the earrings looks like costume jewelry to me and I will guess the stones are not genuine and not of any great value, maybe $10. $15 at the most as they are lovely. The suite of necklace & earrings do look like amethyst cabochons mounted all in sterling silver. That to me is a very nice set and I would hope I could sell it for as much as $75.00 on ebay. Could be worth more to someone else?