diamonds · Sep 21, 2026
Reading a diamond grading report
What an IGI or GIA report tells you, line by line.
Every engagement ring diamond we sell comes with a grading report from IGI or GIA, two independent laboratories. The report is the stone's identity card. Here is how to read one.
The report number
Each report has its own number, and we show it on the diamond's page. You can enter it on the laboratory's website to see the same report, so you know the grades are not ours.
The four Cs
The report lists the carat weight, the colour grade, the clarity grade and, for round diamonds, the cut grade. Our guide to the 4Cs explains what each one means.
Measurements and proportions
You will see the stone's length, width and depth in millimetres, and its table and depth as percentages. These tell you how large the diamond will look from above and how well it is likely to handle light.
Polish, symmetry and fluorescence
Polish and symmetry describe the finish of the facets. Fluorescence describes how the stone glows under ultraviolet light; most of the time it cannot be seen in normal light.
Lab-grown or natural
A report for a lab-grown diamond says so clearly. It is graded on the same scale as a mined diamond.
Questions about a particular report? Ask us and we will go through it with you.
