Diamond guide
Diamond certification
A grading report is a lab's independent description of a diamond. Here's what it tells you, which labs to trust, and how we check every report against its stone.
On the report
What a grading report includes
- The 4Cs
- Cut, color, clarity, and carat weight
- Measurements
- Length, width, and depth to the hundredth of a millimeter
- Proportions
- Table, depth, crown, pavilion, and girdle
- Plot
- A map of the stone's inclusions
- Inscription
- Many diamonds carry the report number laser inscribed on the girdle, so the stone and report can be matched
The labs
Which reports to trust
- GIA
- The Gemological Institute of America created the 4Cs and is the standard for natural diamonds
- IGI
- Grades most of the world's lab-grown diamonds
- AGS
- You'll still see American Gem Society reports on older stones, and they're well respected
Our standard
How we check every stone
1
Read the inscription
We find the report number on the girdle under magnification.
2
Measure
We confirm the measurements match the report.
3
Compare the plot
We match the inclusions we see to the ones the report maps.
Is an appraisal the same as a grading report?
No. A report describes the diamond's qualities. An appraisal puts a replacement value on a finished piece for insurance, and we prepare those in the store.
Do you check the stone against its report?
Every time. We check the measurements, the inclusions, and the laser inscription if there is one against the report before we show you a diamond.