Trust
Diamond Certification
Why an independent grading report matters and how to read one with confidence.
A grading report is an independent laboratory's written assessment of a diamond's measurable characteristics. It is not an appraisal and it does not state a value. Its purpose is to let you compare stones on a consistent basis.
Every certified diamond listed by Carat Drop is accompanied by a report from the International Gemological Institute (IGI). Carat Drop is an independent retailer and is not affiliated with, or endorsed by, IGI.
What the report contains
A typical lab-grown diamond report documents:
- The report number and issue date
- A statement that the diamond is laboratory-grown, and the growth method where determinable
- Shape and cutting style
- Measurements in millimetres
- Carat weight, colour grade and clarity grade
- Cut, polish and symmetry grades
- Fluorescence
- Table and depth percentages, girdle and culet descriptions
- A plotted diagram of clarity characteristics
Laser inscription
Most certified diamonds carry a microscopic laser inscription on the girdle — the thin outer edge of the stone. The inscription usually repeats the report number and often notes that the diamond is laboratory-grown. It is invisible to the unaided eye and requires magnification to read.
You can enter the report number into the issuing laboratory's public report-check service to confirm that the details match the stone you received.
Continue reading
Diamond Shapes
How each outline behaves in the light, which proportions matter, and how shape influences perceived size.
The 4Cs
Carat, colour, clarity and cut — what each grade actually measures and where it matters most.
Understanding IGI Reports
A section-by-section walkthrough of an IGI laboratory-grown diamond report.