Diamond Market, Week 33, 2026

New listings fell 35% week on week, from 1.9 million to 1.2 million, the sharpest single-week supply contraction in seven weeks. That alone tells the story of W33: the market pulled back hard on the input side while off-market removals climbed 24% to 211,000. Total inventory value dropped nearly $4.5 billion, landing at $110 billion. This wasn't a broad price correction so much as a volume story, though prices did soften too.

The price picture is mixed and worth separating. Median price per carat barely moved, up a nominal $1.50 to $932, but the median listing price fell from $1,130 to $1,099, a 2.7% slide. The carat weight story explains part of that: the median active stone shrank from 1.31ct to 1.28ct, a seven week low. Buyers are looking at slightly smaller stones on average, and the cheaper end of the size range is seeing more activity. Whether that's a consumer preference shift or an artefact of which listings survived the week's culling is hard to say. Probably both.

Lab-grown share slipped to 64.5%, its lowest point in the seven weeks I've been tracking this window. It's a modest move, under a quarter of a percentage point, but the direction has been consistent. Natural listings fell harder on volume (down 45.7% in new additions versus 31.1% for lab-grown), yet natural's share of the active pool has quietly edged back. Natural stones median at $1,372 against $784 for lab-grown, and on a per carat basis that gap is stark: $2,222 versus $454. The two markets are increasingly operating on different tracks, with lab-grown absorbing the softer price pressure more visibly.

Shape pricing had a wild week. Asscher was the standout gainer, median up 18.5% to $1,952, on 13,203 new listings. That's a genuine move, not a volume mirage. Hearts collapsed: median down 51.7% to $828, though the composition of new heart listings shifted heavily toward smaller, cheaper lab-grown stones, so this reads more like a mix effect than a demand problem. Rounds, by far the biggest volume category at 41.8% of new listings, saw median slip 27.8% to $702. Oval held better at $1,020. The Asscher pop is the one number I'd watch for confirmation next week.

Cross-retailer overlap nudged up to 50.9%, and the median spread across retailers carrying the same stone widened to 81.3%. That spread is the second highest in the seven week window, with a peak of 85.8% back in W27. When overlap rises alongside spread, it usually means shared inventory is being priced more divergently rather than retailers converging. For a buyer, that's a reminder that shopping the same stone across sites still yields meaningful differences.

The week's standout stone: a 50.5ct D VS1 GIA certified pear, natural, listed at $4.8 million. On the lab-grown side, a 65.08ct cushion in H VS2, IGI certified, at $202,521. The price per carat contrast there is about as clean an illustration of the two markets as you'll find. Going into W34, I'm watching whether new listing volumes recover toward the 1.4 to 1.5 million range that has been more typical, and whether Asscher's price move sustains or fades back into the noise.

Diamond Market Charts, Week 33, 2026 (10 to 17 August 2026)

The five charts below summarise what the diamond market did during 10 to 17 August 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 32, 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.