The Tiffany Diamond Certificate certifies the authenticity, integrity and grades of your Tiffany diamond, and is backed by our Full Lifetime Warranty. Other diamond reports, including those from the Gemological Institute of America (GIA), do not carry such guarantees and even carry disclaimers that the contents of the reports, including diamond grades, may differ if the diamond is examined in the future. Tiffany not only maintains the highest grading standards but also holds itself accountable for the accuracy of its diamond grades.