Market Trends
The IDEX Listed Diamond Price Index
A chain-linked, like-for-like, carat-weighted index of the priced IDEX catalogue shapes, 100 on 14 December 2005, with its composition one click away.
01 · Market Intelligence
Where the diamond market moves, and how much.
One modular product for the listed diamond market: the headline index, every segment's performance, the biggest movers, listed supply and volatility, read against more than twenty years of IDEX market data, with an AI analyst that answers from the same data.
Scroll inside the tool to see every module. Listed asking prices, not transaction prices.tools.idexonline.com
53.84IDEX Listed Diamond Price Index on 28 Oct 2026 (provisional), 100 on 14 Dec 2005
888,545matched stones in the latest like-for-like step, 97.7% coverage
894,508diamonds listed on IDEX with a price, 27 Oct 2026
66shape and carat segments compared for the 30-day movers, 28 Oct 2026
The modules
From the whole market to a single segment.
Each module answers one question about the listed market. Together they form one product: a company receives the modules it needs, and they share one set of periods: the index, the Performance Explorer and the heatmap from 7 days to the full history, movers and supply over up to a year, volatility over up to five years.
Market Trends
Performance Explorer and Market heatmap
Up to four series rebased to 100 on one chart, and a heatmap of every carat group against colour or clarity bands.
Market Movers
The largest rises and falls
Segments ranked by per cent or by amount per carat. Segments with too few matched stones are listed apart and never ranked.
Supply Depth
What is listed, and where
The number of diamonds listed on IDEX by shape, carat group and grade, and how it changed. It counts IDEX listings, never total market supply, and marks days when IDEX's listing base changed.
- Listed on 27 Oct 2026894,508
- Grades listed13,394
- Round share53.0%
Market Volatility
How steady a segment is
Daily moves of like-for-like listed asking prices, with the typical move, the largest rise and fall, and a stability band against the index. Not annualised.
- Index, daily volatility, 30 days0.13%
- BandsStable · in line · volatile · very volatile
IDEX AI
The AI Analyst
Ask about the market in your own words. The analyst looks the figures up in IDEX data, names the period and shows its tables; unverified figures are withheld.
How IDEX AI works Market Trends · the record since 2005
Every move of today, set against two decades.
The index and three of its segments, monthly from 14 December 2005 to 28 Oct 2026. The index, the Performance Explorer and the heatmap read any period of this record, from the last seven days to the whole of it.
Monthly values, 100 = 14 Dec 2005. Like-for-like listed asking prices per carat, not transaction prices. The last month is provisional (28 Oct 2026). Days missing from the IDEX archive, about 5% of the record, are IDEX estimates; the tools mark them. 28 Oct 2026: 8,929 grades · 888,545 matched stones · 97.7% coverage
Market heatmap
See at a glance which part of the market moved.
Rows are carat groups, columns colour bands; each cell is the like-for-like change of the listed asking price per carat over the period. This is the round heatmap for the 30 days to 28 Oct 2026, exactly as the tool served it.
Asking prices, not transactions. Market Intelligence measures the prices diamonds are listed at on IDEX. It does not report sales, demand or the reasons a price moved.
| Carat | D–F | G–H | I–J | K–M | All |
|---|---|---|---|---|---|
| 0.50–0.69 ct | −2.3% | −1.0% | −0.1% | +0.4% | −1.6% |
| 0.70–0.89 ct | −1.6% | −1.2% | +1.4% | +0.3% | −1.1% |
| 0.90–0.99 ct | −1.8% | −1.6% | −0.2% | +1.4% | −1.2% |
| 1.00–1.49 ct | −2.0% | −1.1% | −0.2% | +0.8% | −1.3% |
| 1.50–1.99 ct | −2.0% | −1.3% | −0.7% | +0.5% | −1.3% |
| 2.00–2.49 ct | −0.1% | +0.3% | −1.2% | +0.4% | −0.2% |
| 2.50–2.99 ct | 0.0% | −0.9% | −1.5% | +0.9% | −0.5% |
| 3.00–3.49 ct | −0.7% | +0.2% | −1.0% | +0.4% | −0.4% |
| 3.50–3.99 ct | −0.1% | +1.3% | −0.1% | −1.2% | +0.1% |
| 4.00–4.99 ct | 0.0% | +1.2% | +0.2% | +0.4% | +0.5% |
| 5.00–5.99 ct | +0.6% | +1.8% | +0.4% | −0.1% | +0.9% |
IDEX AI Analyst
Questions in plain words, answers in IDEX figures.
Built into Market Intelligence in the Retailer Hub. The analyst answers only from IDEX tool results, says when the data cannot answer, and gives no forecasts and no investment advice.
IDEX AIMarket Intelligence AI AnalystVerified
Which diamond segments are gaining or losing value?
Cushion, 0.50–0.69 ct, I–J led the gains (+9.00%), while Princess, 0.70–0.89 ct, K–M led the declines (−8.47%).
These are the strongest movers by percentage across shape × carat group × colour band for 2026-09-28 to 2026-10-28. The 2026-10-28 snapshot is provisional.
Largest gains
| Rank | Segment | Change | Matched stones |
|---|---|---|---|
| 1 | Cushion · 0.50–0.69 ct · I–J | +9.00% | 295 |
| 2 | Pear · 5.00–5.99 ct · D–F | +3.88% | 97 |
| 3 | Oval · 4.00–4.99 ct · D–F | +3.45% | 109 |
| 4 | Emerald · 3.00–3.49 ct · D–F | +2.66% | 214 |
| 5 | Cushion · 0.70–0.89 ct · K–M | +2.62% | 129 |
Largest declines
| Rank | Segment | Change | Matched stones |
|---|---|---|---|
| 1 | Princess · 0.70–0.89 ct · K–M | −8.47% | 171 |
| 2 | Cushion · 0.50–0.69 ct · D–F | −8.22% | 1,969 |
| 3 | Princess · 0.70–0.89 ct · I–J | −7.22% | 1,293 |
| 4 | Pear · 3.00–3.49 ct · K–M | −6.64% | 101 |
| 5 | Oval · 3.00–3.49 ct · K–M | −6.54% | 131 |
Changes measure like-for-like listed asking prices per carat, not transaction values. Segments with insufficient observations or coverage are excluded from the rankings.
What are the most important market changes this month?
Where you use it
In your workspace, on your website, in your systems.
One set of IDEX market data behind every channel: a figure means the same in the Hub, on your website and in the API.
Your team's workspace
Market Intelligence and its AI Analyst in your team's Workspace, next to your other IDEX tools.
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On your own website
The Market Intelligence widget on your own website, with the modules you choose, styled to your brand in the Widget Designer.
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In your own systems
The index, movers, heatmap, supply and volatility as JSON from the IDEX Data Platform API, documented and explorable in the Hub.
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Read the market with IDEX.
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