Diamond Market, Week 12, 2026

Off-market listings exploded this week. 1,325,050 stones left active inventory across the retailers I track, up from just 56,591 the prior week. That's not a rounding error. It's a 22x surge in a single week, and it sets a record high for the seven periods I have on file. New listings came in at 1,997,752, down about 7% from week 11, so the net effect was a much tighter inflow-to-outflow ratio than we've seen recently. Active inventory still grew to a record 25.4 million stones, but the pace of that growth is clearly slowing. Worth watching whether this off-market spike was a one-week clearance event or the start of a genuine pullback in listed supply.

Prices are doing something slightly counterintuitive against that backdrop. The median price per carat ticked up $20.85 to $1,073.85, yet the median stone price fell to $1,105, a record low for the window. The explanation sits in the median carat figure, which dropped from 1.29ct to 1.23ct this week. Smaller stones, priced more keenly, dragging the median sale price down even as per-carat rates nudged higher. Across the seven-week run, median price per carat has fallen around 27% from its peak of $1,492.20, so this week's modest recovery doesn't change the broader direction yet.

Lab-grown share reached a fresh high at 63.3% of active inventory, continuing a steady climb from around 59% in weeks six and seven. The pricing gap between origins remains wide. Natural stones came in at a median $1,453 for new listings, lab-grown at $839.16, so roughly 73 cents on the dollar if you're comparing like-for-like at the median. What's striking this week is the natural median price moved sharply, down 27% from $1,990.95 the prior week, while lab-grown slipped a more modest 5.6%. That natural price drop is worth treating with some caution given the large off-market volumes; the mix of what's still listed may simply have shifted toward smaller or lower-colour stones.

Shape pricing had some genuine movement. Trillion cut stones, admittedly a thin market at just 470 new listings, posted a 60% jump in median price to $934.40. That's a small enough sample that one cluster of quality stones can move the number. Radiant is more meaningful: 65,517 new listings and a 20.7% price rise to $1,356.80 carries real weight. Heart shapes also gained, up nearly 14% to $1,374. On the other side, emerald cut median fell 13.6% to $1,179.94 and princess dropped 14.8% to $1,130, both on solid volumes. Round continued to dominate new listings at 60.3% share, with a median of $880, unchanged in direction if not quite in tone.

Cross-retailer overlap reached 47.2%, another record for the window, meaning nearly half of all active stones appear across more than one retailer. That figure has risen steadily from 31.4% in week six. The concentration story is similar: the top five sources of new listings accounted for 33.7% of all new supply, meaning the broad base of the market is still fragmented but the top end is doing a disproportionate share of the restocking work. With the spread metric easing slightly to 89.2% from 90.3%, there's a very modest sign that pricing dispersion across retailers is beginning to narrow, though it's still wide by any historical standard.

The question heading into week 13 is whether that off-market surge repeats or reverses. If listings continue to be pulled in large numbers while new supply also moderates, active inventory could plateau or even contract for the first time in this seven-week run. That would change the pricing dynamic meaningfully, particularly for naturals where the median has been under consistent pressure. Buyers sitting on the fence for a well-cut natural round in the 1.2ct to 1.5ct range may find the current median levels near $2,233 per carat worth acting on before supply tightens.

Diamond Market Charts, Week 12, 2026 (16 to 23 March 2026)

The five charts below summarise what the diamond market did during 16 to 23 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 11, 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.