AGS Certified 1/2ct tw Round Diamond Stud Earrings in 14K Yellow Gold 1/2ct total weight in 14K Yellow Gold with friction ( push) backs. These include a certificate from AGS the American Gem Society 1/2ct total weight means 1/4ct for each diamond. When shopping for a diamond, trust the AGS Laboratories. We protect consumers by providing expert, third-party evaluation of a diamonds quality characteristics. 1/2ct total weight in 14K Yellow Gold with friction ( push) backs. These include a certificate from AGS the American Gem Society 1/2ct total weight means 1/4ct for each diamond. AGS (American Gem Society Certificate Included). Each earring is numbered and tagged by AGS with a unique number corresponding to the number on the certificate, which can be searched on their website.