Understanding Diamond Certification

A diamond certificate is not a valuation and not a guarantee of quality. It is something more useful than either: an independent laboratory’s written record of exactly what a stone is, assessed by people with no interest in selling it to you.

What the report actually contains

Beyond the four Cs, a full report records the stone’s measurements, its proportions, the polish and symmetry of the finish, whether it fluoresces under ultraviolet light, and a plotted diagram of its internal characteristics. That diagram is effectively a fingerprint — no two stones plot identically.

Why the laboratory matters

Grading involves judgement, and different laboratories apply their standards with different degrees of consistency. A stone graded generously in one report may sit two grades lower in another, and the price difference between those grades is real. Reports from the most established laboratories cost more to obtain precisely because their grading holds up.

• Check the report number is laser-inscribed on the stone’s girdle where applicable.
• Verify the report online through the issuing laboratory before you buy.
• Match the measurements on the report against the stone in front of you.
• Treat an in-house or vendor-issued appraisal as marketing, not certification.

We supply independent certification with every certified stone we sell, and we are glad to walk you through the report line by line. A certificate you do not understand is doing only half its job.