Week 11, 2026

Off-market activity collapsed this week. Only 56,591 listings left the market across all the retailers I track, down 83% from last week's 338,873 and the lowest single-week exit figure in the seven-week window I'm looking at. That's not a rounding error. Sellers are holding. And with 2.15 million new listings arriving in the same period, active inventory climbed another 9.3% to a fresh record of 24.76 million stones. The market is filling up faster than it's clearing.

The inventory expansion has been relentless since W05. Active count has more than doubled in seven weeks, up 140%, and total listed value now sits at $84.7 billion, also a seven-week high. What's interesting is how that growth is being composed. Lab-grown share ticked up again to 62.44%, its highest point in the window, with lab-grown contributing 1.62 million of the week's new arrivals versus 535,000 natural. The per-carat price picture tells you something about what's driving the volume: lab-grown median price per carat came in at $480.89, down 19% from last week, while the stones themselves are getting larger (median active carat reached 1.29, another record). More carats, lower per-carat cost. The maths on that combination tends to attract volume buyers, and the listing count reflects it.

Natural diamonds moved the other way on price. Median transaction price for natural new arrivals jumped to $1,990.95, up 47% week on week, with per-carat median rising a more modest 12.8% to $2,595. That divergence between the two origin types is genuinely significant. Lab-grown is getting cheaper per carat while going larger; natural is getting more expensive. Whether that's a real repricing or a shift in what's being listed (more large, high-grade naturals entering this week) is worth watching. The natural exit rate fell sharply too, with only 29,222 naturals going off-market versus 130,500 last week. Sellers aren't pulling stock, which usually means they're not finding buyers at the prices they want, or they're patient enough to wait.

Shape pricing threw up some eye-catching numbers. Princess cut median new-listing price rose 79% to $1,326, and Asscher moved 64% to $1,510.57. Round remained the dominant shape by volume at 39.6% of new listings, with a median of $930, well below the overall median. The cross-retailer spread reached a seven-week high of 90.3%, meaning the price gap between the cheapest and most expensive listing for the same stone across retailers I follow is wider than it's ever been in this window. That's a meaningful signal for buyers. The spread between what a well-informed shopper pays and what an uninformed one pays is at its widest point since I started tracking this run.

The price-per-carat trend is the one I keep returning to. At $1,053, it's down 29% from the $1,492 reading in W07 and sitting at a seven-week low. Median listed price hasn't fallen by the same magnitude (only down 9% from peak), which tells you the carat size inflation is absorbing some of that per-carat softness. A buyer getting more carats for roughly the same outlay looks like a bargain. Whether it holds depends on whether this inventory wave eventually forces genuine price cuts, or whether off-market activity stays suppressed and the supply just sits. That's the question going into next week.

Lucy Market Index

Ten numbers I record every snapshot.

Versus Week 10, 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.