Where are diamond serial numbers registered?

Diamond serial numbers are typically registered with the gemological laboratories that grade and certify the diamonds, such as the Gemological Institute of America (GIA) or the International Gemological Institute (IGI). These laboratories assign unique serial numbers to diamonds, which are then laser-inscribed on the diamond's girdle. This registration helps ensure the authenticity and traceability of the diamond, allowing buyers to verify its characteristics and certification details.