Almost nothing that determines a gemstone's value can be judged reliably by eye. Whether a stone is natural or laboratory-grown, whether its colour has been enhanced, and how its clarity compares with another stone the same size are all laboratory findings. A grading report turns those findings into something written down and checkable.
Report number and date
Every report carries a unique reference and the date of examination. That number is what lets you retrieve the laboratory's own record and confirm it matches the paper in your hand. On a certified diamond it is often laser-inscribed on the girdle as well.
Shape, cut and measurements
The cutting style and the stone's dimensions in millimetres. This is worth more attention than most buyers give it: two stones of identical carat weight can differ noticeably in how large they look face-up, depending on how the weight is distributed.
Carat weight
Weight, not size, recorded to two decimal places. A deep-cut stone carries weight below the girdle where nobody sees it.
Colour and clarity
Where the stone falls on the laboratory's scales, assessed under controlled lighting. Scales differ between laboratories, which is why comparing two stones only works when both were graded by the same one.
Cut, polish and symmetry
How well the stone was cut and finished. This governs brilliance more than any other single factor, and it is the grade most often overlooked in favour of carat weight.
Origin, treatment and comments
Natural or laboratory-grown, any treatment detected, fluorescence, and anything else the grader recorded. This section is the one that changes what a stone is worth.
Verify it yourself
Take the report number to the issuing laboratory's own verification service — not to the seller's. Every figure should match. If a single one does not, raise it before anything else.
