GIA graded natural diamonds
An independent record of a natural diamond’s identity.
By the CTJ Jewellery team, led by founder Greg Ward · Updated September 2026 · Editorial policy
Key facts
- GIA: Gemological Institute of America, founded 1931
- Developed the four Cs grading system
- Reports state natural or laboratory-grown origin
- GIA can laser-inscribe the report number on the girdle
- GIA graded natural studs available with a report per diamond
- Also known as a GIA certificate
What does a GIA report include?
Shape and measurements, carat weight, colour grade, clarity grade with a plotted diagram of inclusions, cut, polish and symmetry for round diamonds, fluorescence, and the report number.
Grading reports explainedHow do I check a GIA report?
Match the report number to the laser inscription on the diamond’s girdle, and confirm the measurements and weight match. We’re happy to show you both under the loupe.
Is a GIA report enough to choose a diamond?
No. A report records grades, not beauty.
Two natural diamonds with identical reports can look very different. That’s why we select diamonds for visual performance and encourage you to compare them in person.
GIA or IGI for a natural diamond?
Both are internationally recognised and independent. GIA is long established as a reference for natural diamonds, and IGI grades both natural and lab-grown. What matters most is that the report is independent and matches the diamond.