For a small fee you can have it appraised over at the NAWCC site. How accurate any appraisal will be is only educated guesswork. While the jeweler can confirm that those 'diamonds' are real along with the quality of those 'diamonds', in my experience most appraisals of jewelry made by jewelers "for insurance purposes" are grossly inflated just to make the owner feel better about the item and reduce the risk of the jeweler being accused of (or sued for) undervaluing an item.