Zales signature collectionâ® this 18k gold engagement ring has one 1-1/4 ct. Round diamond solitaire set in a 4-prong setting. Zales signature diamonds include an official igi appraisal. Your unique appraisal number confirms the quality of your diamond and is laser-inscribed directly on the zales signature solitaire and inscribed in the setting of the earrings and rings.