Appraisal When it comes to certification and appraisal International Gemological Services is committed to a superior standard of accuracy, precision and reliability. An IGS certificate gives you the assurance that you can buy with confidence and DiamondStuds4Less is proud to provide an IGS certificate of diamond quality and diamond replacement value appraisal with these diamond stud earrings. It is one more way we are working to earn your trust and your business.