Week 5, 2026

The number that catches my eye first is off-market activity: only 145,053 listings came off the market in week 5, down 48% from the 279,060 we saw the week prior and the lowest single-week figure across the five weeks I've been tracking 2026. That collapse in removals, combined with another solid week of new supply (496,586 fresh listings), pushed active inventory to a five-week high of 10.28 million stones, with total listed value crossing $32.7 billion. Inventory is accumulating because diamonds are arriving faster than they're leaving. Simple as that.

The supply composition tells its own story. Lab-grown new listings ran at 355,225 for the week, up nearly 26% on week 4, while natural new listings fell 25% to 141,322. Lab-grown now sits at 60.2% of active inventory, a steady climb from 59.5% back in week 1. The price gap between the two origins is closing at the median, though: natural came in at $1,310 (down 9.7% week on week) and lab-grown at $1,334, with the per-carat spread remaining wide at $2,235 for natural versus $976 for lab-grown. Buyers who've been watching that natural median will notice it's drifted noticeably in five weeks.

The spread story is worth a mention. The median cross-retailer price spread on identical stones sits at 63.9%, its five-week low and down from a peak of 64.75% last week. The direction is modest but consistent. Overlap between retailers also ticked down to 33.9%, another five-week low, suggesting the market is fragmenting slightly in terms of which stones appear where. Neither shift is dramatic on its own, but both moving together in the same direction is worth keeping an eye on.

Shape price moves were the most volatile part of the week. Trillion cut median prices swung from $962 to $2,832, a 195% jump, though with only 27 new listings that's a thin sample and I'd treat it cautiously. More meaningful is the oval move: 92,974 new listings came through at a median of $1,366, down nearly 28% from the $1,890 recorded in week 4. Asscher dropped similarly hard, off 32% to $1,486. Heart, by contrast, climbed 25% to $1,594. Round remained the dominant shape by volume at 41.9% of new listings, steady as ever at a median of $1,107.

The notable stones this week include a 50.26ct lab-grown pear graded F/VS1 listed at $134,880 and, on the natural side, a GIA-certified 10.03ct D/FL heart asking $1,506,612. That heart is the most expensive single stone across the retailers I follow this week. The premium for flawless natural colour in unusual shapes remains extraordinary, even as the broader natural median softens.

Going into week 6, the question is whether off-market activity stays this subdued or snaps back. If removals remain low while new supply holds pace, inventory could push through 10.5 million stones. Watch natural median pricing too: three consecutive weeks of softness, and it's now sitting below the lab-grown median at the stone level. That doesn't happen often, and it may not last.

Lucy Market Index

Ten numbers I record every snapshot.

Versus Week 4, 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.