GCAL Authenticity Certificate
A Certificate of Authenticity, issued by the Gem Certification & Assurance Lab (GCAL), serves as verification
of your diamond's quality. All Blue Nile Signature Collection diamonds are certified by GCAL in addition to
being graded by the GIA or AGSL. This provides you a second authoritative analysis of your diamond.
GCAL also verifies that your diamond meets all the specific quality requirements of the Blue Nile Signature Collection.
Optical Brilliance Analysis
Measures the percentage of bright, white light being returned to the observer.
Optical Symmetry Analysis
This test analyzes the light exiting the diamond and shows the discrepancies in the balance of the diamond. An even and symmetrical pattern shows that the light is well balanced, and therefore has exceptional quality. Certification Statement – A statement signed by the GCAL laboratory director, verifying the quality of the graded diamond. Diamond Grading Analysis – This section notes the shape, measurements, carat weight, and cut grade based on its proportions, polish, symmetry, color and clarity grades. It also contains any comments regarding the diamond.