A diamond grading report is an independent lab's record of what a stone is and how it grades. It is true for the day the lab examined the stone.
In more detail
It records whether the stone is natural or laboratory-grown, any treatment, and its four Cs, measurements and proportions. It is not an appraisal: it says what the stone is, not what it is worth. GIA issues its Diamond Grading Report for loose natural diamonds of 0.15 carat and up. Check the inscription, the online record and the measurements to make sure the report belongs to the stone.
On a grading report
GIA's Diamond Grading Report gives the four Cs, a plotted diagram of the clarity characteristics and a proportion diagram. Round brilliants in the D-to-Z range also get a cut grade. GIA grades loose stones only; IGI also reports on set stones, "as mounting permits".
Related terms
- Diamond Dossier: The Diamond Dossier is a shorter GIA report for loose natural diamonds of 0.15 to 1.99 carats, D to Z. It gives the four Cs and a proportion diagram, but no clarity plot.
- Laboratory-Grown Diamond Report: The Laboratory-Grown Diamond Report was GIA's digital-only report for laboratory-grown diamonds, from October 2020 to September 2025. It gave color and clarity grades and stated the growth method, CVD or HPHT.
- Identification Report: An Identification Report states what a material is, without color or clarity grades. GIA issues one for simulants and for diamonds with unstable treatments, such as coating or fracture filling.
- Appraisal: An appraisal is a statement of what a stone or a piece of jewelry is worth. A diamond grading report is not an appraisal.
- Report number: The report number is the unique number a lab gives a report. GIA registers it in its database, so anyone can look it up.
- Four Cs: The four Cs are color, clarity, cut and carat weight: four scales that describe the quality of a diamond. GIA made them into a grading system in the 1950s.