Open data
Caratlytics Diamond Price Index
A monthly index of retail diamond prices. Each release reports the median USD per carat for natural and lab-grown diamonds, computed from a systematic sample of live listings across more than one hundred retailers, with the full series downloadable as CSV and JSON under CC BY 4.0.
Latest release: May 2026
2026-05 Generated 2026-06-12 from live platform data.
$2,262
Natural · Median USD per carat
+0.14% Month over month
$548
Lab-grown · Median USD per carat
+1.02% Month over month
$876
Overall · Median USD per carat
-2.82% Month over month
Natural Lab-grown
Chart values are medians. Shaded band shows the interquartile range for the overall market.
Cross-retailer price spread
When the same certificate is listed by two or more retailers, the spread between the cheapest and the most expensive listing measures market dispersion. Lab-grown dispersion runs far higher than natural.
| Diamonds matched at 2+ retailers | Average spread | Median spread | |
|---|---|---|---|
| Natural | 1,594,145 | 61.8% | 45.6% |
| Lab-grown | 3,663,465 | 117.8% | 95.5% |
Index methodology
- Sample: a systematic 1 in 10 sample of listings (by listing identifier), each contributing its most recent observed price in the calendar month. Monthly observation volumes run in the millions.
- Unit: USD per carat under the platform's pinned conversion rates, which act as a fixed unit of account. The series moves when retailers reprice, never on currency fluctuations.
- Filters: carat 0.25 to 10, price 100 to 100,000 USD per carat, positive prices only. The series begins December 2025, the first month of full collection coverage.
- Segments: natural and lab-grown, classified from the stone's certified origin, plus the overall market. Quartiles are published alongside medians.
- Revisions: releases are immutable once published. A correction is published as a new release with a changelog entry, never as a silent edit.
Cite as: Caratlytics Diamond Price Index, release May 2026, caratlytics.com. Data is licensed CC BY 4.0; attribution to Caratlytics is required.
All releases
| Month | |
|---|---|
| May 2026 | Read more |