Diamond Market, Week 43, 2026

Natural supply came back hard this week. New natural stones hit 437,739, up 259% on week 42's 121,782, and that pushed total new arrivals to 975,295, more than double the prior week. Retirements actually slowed, down 10% to 484,383. So the market added roughly 490,000 stones net in seven days. Active inventory closed at a record 49.0 million stones worth $156.1 billion, and both figures have climbed every week bar one since early September (inventory is up 63% across the window I'm tracking).

But all that extra stock hasn't moved headline prices much. The median asking price slipped 0.8% to $1,089, and the median price per carat eased 1.6% to $844. That per carat figure has drifted down about 7% over seven weeks, from a peak of $932 in week 38. Meanwhile the median active stone grew to 1.32ct, a new high. Bigger stones at a lower rate per carat is a buyer's combination, and it's been building quietly for a while.

Lab-grown share barely shifted, up half a point to 62.5%, which keeps it inside the narrow 61.7 to 63.5% band it's held since September. Inside the new arrivals, though, lab-grown pricing jumped. The median new lab-grown stone came in at $808, up 16.8%, and per carat rose 15.8% to $391. Natural arrivals firmed more gently, up 3.4% to $889, with per carat up 7% to $1,773. That's still roughly 4.5 times the lab-grown rate. One week of firmer lab-grown listings isn't a trend yet. Worth watching, though, because it cuts against months of deflation in that category.

Now the spread story. Cross-retailer overlap fell to 41.6%, the lowest reading in seven weeks, while the median spread on stones listed in more than one place widened to a record 133.9%. Back in week 38 it sat at 84.9%. Fewer shared stones, and wider gaps on the ones that are shared. Even the top of the market shows it: the week's priciest stone, a 23.41ct D FL natural oval with a GIA report, appeared at both $3,459,813 and $3,331,671. That's a $128,000 difference for the same diamond. A handful of names accounted for 41.5% of new listings, which goes some way to explaining why so much fresh stock exists in only one place.

Shape pricing split in two. Step cuts and marquise fell sharply: asscher down 19.4% to $968, emerald down 17.2% to $865, marquise down 16.9% to $863. Radiant went the other way, up 8.7% to $1,130, and cushion rose 6.6% to $1,363. Round still dominated volume at 40.8% of new listings, with a median of $742. Novelty shapes nearly doubled in median price, though at just over 38,000 listings I'd treat that as mix, not demand.

Going into week 44, I'm watching whether natural supply keeps flowing at this pace or whether week 43 was a one off restock. And if the spread stays above 130%, the case for comparing before buying is the strongest it's been all season. For emerald and asscher buyers, this is a solid window. Prices on those cuts just reset lower, and the supply is there.

Diamond Market Charts, Week 43, 2026 (19 to 26 October 2026)

The five charts below summarise what the diamond market did during 19 to 26 October 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 42, 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.