Diamond Market, Week 13, 2026

The number that stops me cold this week is the price-per-carat figure. $987.50, the first time the market-wide median has broken below $1,000 in this seven-week window, and down 8% from last week's $1,073.85. Over the full window it's fallen 34%, from $1,492 in week seven. That's not noise. Total active inventory hit a new record of 27.7 million stones, up nearly 9% week on week, and new listings surged 83% to 3.65 million for the period. When supply expands that fast, price-per-carat tends to feel it. This week, it did.

Lab-grown is driving the volume story, and the numbers are stark. Lab-grown new listings more than doubled week on week, up 101% to 2.85 million, pushing lab-grown's share of total active inventory to 65.3%, a record for this window. The median price-per-carat for lab-grown stones fell to $532, down 33% from last week's $797. That's the compositional drag pulling the market-wide figure below $1,000: more lab, and cheaper lab, arriving faster than it's leaving. Natural stones are a different story. Their median listing price rose 25% to $1,811 and price-per-carat climbed to $2,474, up roughly 11%. Natural new listings grew 36% but off-market natural volumes actually fell slightly. The two origin segments are moving in genuinely opposite directions right now.

The cross-retailer overlap and spread figures are worth sitting with. Overlap reached 48.5%, another record, meaning nearly half of all active stones appear across multiple retailers simultaneously. The median spread between the cheapest and most expensive listing for the same stone hit 92.7%, also a record for this window. These two moving together tells you something about how the supply glut is playing out: the same inventory is being listed more widely, and the pricing discipline across those listings is loosening. Buyers willing to shop across retailers are finding meaningful differences on identical stones. That spread has widened from 63.5% in week seven. Not a trivial shift.

Shape pricing was mixed but a couple of moves stand out. Rounds ticked up 14% to a median of $1,005 on very high volume, 1.32 million new listings, a 36% share of all new stock. Ovals followed with a 12% gain to $1,100. Cushions dropped 8% to $1,530 and trillions fell nearly 16% to $786, though trillion volumes are thin enough (under 5,000 new listings) that one read shouldn't be over-interpreted. The "other" shape category showed a wild median swing to $2,813, but that's a small, heterogeneous bucket and almost certainly a compositional artefact rather than a genuine pricing move.

Off-market listings also hit a seven-week record at 1.38 million, which is notable context. Inventory is piling up, but stones are also cycling out at a pace not seen earlier in this window. That turnover, combined with the surge in new supply, suggests the market is churning rather than simply accumulating. Whether that resolves into a price floor or continued compression is the question worth watching heading into week 14. If lab-grown supply keeps arriving at this rate and natural stones continue to hold or gain, the gap between those two segments will widen further, and the market-wide median will keep telling a story that is really two very different stories averaged together.

Diamond Market Charts, Week 13, 2026 (23 to 30 March 2026)

The five charts below summarise what the diamond market did during 23 to 30 March 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 12, 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.