GIA is the most widely trusted grading lab for natural diamonds in the US market. When a seller references a GIA report number, you can verify the report and match the stone to its specs.
At a glance
- Best for: natural diamonds, resale confidence
- What it includes: 4Cs, polish, symmetry, fluorescence, proportions diagram
- Watch for: very high color grades with strong fluorescence
How to use it
Ask for the report number and verify it before you buy. Compare the table, depth, and crown/pavilion angles to your cut goals, and cross-check clarity characteristics against the plotting diagram.
If you are still learning the 4Cs, start with the 4Cs guide and then revisit the report with a trained eye.
