Open data
Open data
Price by grading laboratory.
Median USD per carat by grading laboratory, tracked monthly. Differences reflect both the stones each lab tends to grade and how the market prices each report.
GIA · Natural median / ct
$2,242
IGI · Natural median / ct
$1,633
GIA versus IGI
+37%
Median natural USD per carat, GIA relative to IGI, latest month.
GIA
IGI
HRD
EGL
OTHER
Dec ’25Jan ’26Feb ’26Mar ’26Apr ’26May ’26Jun ’26Jul ’26Aug ’26
Each point is the median USD per carat from a systematic 1-in-10 sample of listings, one observation per listing per calendar month, in pinned-rate USD. Cells below 150 sampled stones in a month are withheld rather than shown.
Latest median by laboratory
| Laboratory | Natural | Lab-grown |
|---|---|---|
| GIA | $2,242 | $1,142 |
| IGI | $1,633 | $446 |
| HRD | $2,639 | · |
| GCAL | · | $1,059 |
| EGL | $2,702 | · |
| OTHER | $2,490 | $1,045 |
Cite as: Caratlytics Diamond Price Index, 2026-08, caratlytics.com. Licensed CC BY 4.0.