Diamond Market, Week 4, 2026

The quietest exit rate in four weeks is the most telling number from week 4 of 2026. Only 279,060 stones came off the market, down 35% from the prior week's 432,612 and the lowest off-market count across the entire four-week window. Fewer removals, combined with a still-solid 471,635 new listings, pushed active inventory to a fresh four-week high of 9.93 million stones valued at $31.8 billion. Supply is accumulating. The pipeline isn't draining.

Price per carat keeps climbing despite that supply build, which is the interesting tension this week. The median hit $1,493.33 per carat, up 2.3% from last week and a new four-week peak, having risen 3.2% since week 1. Median transaction price, by contrast, dipped fractionally to $1,226.82, the lowest in the window. That divergence suggests the mix is shifting toward heavier stones at better per-carat rates, even as headline prices drift slightly. The median active stone sits at 1.21 carats, matching last week and the highest of the run.

The spread story is worth flagging. The median cross-retailer price spread widened to 64.75% this week, also a four-week high and sitting about 1.1% above the window average. When the same stone is priced that far apart across the retailers I track, it generally means either the market is fragmenting on valuation or one end of the distribution is repricing faster than the other. Lab-grown median prices surged 31.5% week on week to $1,510, while natural moved a more measured 5.6% to $1,450.22. The spread widening aligns with lab-grown repricing unevenly across the market.

Shape moves were dramatic on paper but need context. Oval new listings came in at a median of $1,890, up nearly 60% from the prior week's $1,183. Asscher jumped 55% to $2,180, and cushion moved 43% to $2,280. These aren't gradual drifts, they're sharp compositional shifts, almost certainly driven by the mix of stones added this week rather than organic price inflation. Round remained the volume anchor at 38.7% of all new listings, with a median of $1,076, unchanged in character. Heart was the one shape that genuinely fell, dropping 16.7% to a median of $1,275 across 13,192 new listings.

Concentration is worth tracking alongside supply growth. The top five names by new listings accounted for 67.3% of all additions this week, meaning a handful of names did most of the listing while the broader tail contributed far less. That's fairly concentrated for a market of this size, and it shapes how reliable cross-retailer pricing signals actually are. The 34.83% overlap rate, a four-week high, confirms that the same stones are increasingly appearing across multiple retailers simultaneously, which typically supports comparison shopping but also compresses the information advantage any single retailer holds.

Going into week 5, the off-market rate is the signal I'm watching most closely. Four straight weeks of falling exits, with new listings also contracting sharply from the week 1 spike, suggests the post-holiday restock surge is normalising. If exits stay suppressed and listings continue falling, inventory will keep building even without strong consumer demand. Whether that tips into visible price softening at the median level, or whether the per-carat trend holds, will depend on whether lab-grown repricing this week was a real shift or just a compositional artefact from the new-listing mix.

Diamond Market Charts, Week 4, 2026 (19 to 26 January 2026)

The five charts below summarise what the diamond market did during 19 to 26 January 2026. Each is a static image you can save or share. Together they cover where prices sit today, how inventory is moving, the lab-grown versus natural mix, where retailers raised or cut prices, and how much the same stone can vary across competing sellers.

Lucy Market Index

Ten numbers I record every snapshot.

Versus Week 3, 2026

Biggest shape movers

Recent trends

How metrics are tracking across the recent window of snapshots.

How the Lucy Market Index has moved

By origin

Top shapes by new listings

Notable stones

Each stone links to its full Carat Hunter listing.