1-carat polished up 0.5% in August, first rise in 15 months
Rapaport's index shows small rounds leading the recovery, with the 0.30-carat up 2% and the 0.50-carat up 2.5%. The 3-carat slipped 0.4% after 18 months without a move.
By The Diamond Desk
What changed
The 1-carat rose. Rapaport's asking-price index for 1-carat rounds gained 0.5% in August, its first increase in 15 months, after a flat July. Every size below one carat rose more. The 3-carat, unmoved for 18 months, fell.
What it means
- If you restock for the holidays: the 0.30 to 0.69-carat band is genuinely firmer. Price replacement stock off this month's asking prices, not last spring's.
- If you hold 3-carat goods: check the estimate book. Eighteen months of one steady number just ended.
- What this is not: a demand recovery. Supply cuts made this rise, and September's fairs will test it.
Key figures
| 1-caratfirst rise since May 2025 | +0.5% |
|---|---|
| 0.50-caratthe month's best size | +2.5% |
| 0.30-caratsecond month rising | +2.0% |
| 3-caratfirst move in 18 months | −0.4% |
Source: RAPI, August 2026 · published 2 Sep 2026, 08:21 UTC
Supply cuts, not buyers returning
Rapaport credits supply. Miners and manufacturers cut production, and the sizes that fell hardest in 2025 rebounded as the imbalance closed. Trading picked up after the summer slowdown, and rounds outperformed fancy shapes.
Geography helped. Indian manufacturers shipped to the United States once July's confirmation of a 10% US tariff on Indian goods removed months of uncertainty. Business at the Mumbai show, IIJS, was brisk, while Antwerp and Israel were seasonally quiet. Chinese buyers stayed slow ahead of the Hong Kong fair in September.
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May 2025 · the last rise before this oneJun 2025 to Jul 2026 · flat or down every month, July flatAug 2026 · +0.5%
The 3-carat turned the other way
It slipped 0.4% after what Rapaport calls a year and a half of steadiness. That ends the condition Carat Capital reported on 4 August: July was the first month since March 2025 with nothing falling. It lasted one month.
Small goods carry it. Over July and August together the 0.50-carat is up 4.35% and the 0.30-carat 3.63%, on Carat Capital's compounding of Rapaport's monthly figures. The spread between the best and worst size is 4.55 points.
August, by size · zero line at centre-left
Source: Rapaport · 2 Sep 2026 · Round D–H IF–VS2
Miners are still reporting declines
The same release lists what has not repaired. Alrosa's first-half revenue fell 36% year on year and it booked a loss. De Beers' first-half revenue fell 19% to $1.58 billion. Both were reported here when they were published.
A monthly index is a monthly index. Carat Capital's own price list still carries the 1-carat RAPI level as a July point. It will show August's move when the level is revised, not before.
| Size | July | August | Jul + Aug |
|---|---|---|---|
| 0.30-carat | +1.6% | +2.0% | +3.63% |
| 0.50-carat | +1.8% | +2.5% | +4.35% |
| 1-carat | 0.0% | +0.5% | +0.50% |
| 3-carat | +0.2% | −0.4% | −0.20% |
Source. Rapaport monthly releases, 4 Aug and 2 Sep 2026.
Jul + Aug. is Carat Capital's compounding of the two.
What to watch
- 4–8 SepVicenzaoro, Vicenza. The first fair where August's asking prices meet order books.
- SepJewellery & Gem World, Hong Kong. Rapaport reports Chinese demand slow ahead of it.
- Early OctRapaport's September reading. A second gain in the 1-carat makes August a floor, not a bounce.
The story so far
- The 1-carat stops fallingJuly flat, every other size up.
- Zero for Antwerp10% on polished finished in India; zero on Belgian and Botswana cuts.
- De Beers narrows the lossH1 revenue down 19%.
- Alrosa books the lossH1 revenue down 36%.
Go deeper
What would change this call
A September reading in which the 0.30 and 0.50-carat gains reverse while Vicenzaoro and Hong Kong report thin order books. That would mean the rebound was inventory clearing, not a floor, and the holiday restocking advice above would be withdrawn.
How RAPI is built
The Rapaport Trade Diamond Index tracks asking prices, not settled trades. For each of the top 25 quality categories of round diamonds listed on Rapaport Trade, the marketplace formerly called RapNet, it averages the asking prices of the cheapest tenth of stones. The headline series are D to H colour, IF to VS2 clarity, at 0.30, 0.50, 1 and 3 carats. It is published monthly.
Method
The “Jul + Aug” column compounds Rapaport's July and August figures: (1 + July) × (1 + August) − 1. For the 0.50-carat, 1.018 × 1.025 = 1.0435, so +4.35%. The 4.55-point spread is +4.35% less −0.20%. Carat Capital's price list carries the 1-carat RAPI level as a July 2026 point, marked provisional, and does not yet reflect August's 0.5%.