Diamond Market, Week 20, 2026

Only 398,586 stones came off the market this week, a 77% drop from the prior week and the lowest figure I've tracked across the last seven periods. For context, week 19 saw nearly 1.74 million removals. That kind of collapse, paired with over 1.13 million new listings still flowing in, means inventory is building. Active stock rose 3.6% to just over 26.27 million diamonds, worth a combined $85.6 billion. Stones are arriving and they're staying put.

Median price held steady at $1,072.50, barely moving from the prior week's $1,070. But median price per carat tells a different story, falling 4.3% to $985.92. That's the lowest reading in the window I track and reflects a shift in the composition of what's being listed. Natural diamonds saw their median price drop nearly 19% week on week to $1,235, while lab-grown median prices jumped over 20% to $951.55. The per carat gap between origins is compressing: naturals sit at $2,077 per carat, lab-grown at $612. Lab-grown's share of total inventory eased slightly to 65%, down from 66% last week, though over the broader window it hasn't moved much at all.

The spread story deserves attention. Median cross-retailer spread hit 90.4%, a new seven period high. That means when the same stone appears at multiple retailers, the gap between the cheapest and most expensive listing is wider than it's been in nearly two months. For buyers, this is a clear signal: shopping around isn't optional, it's where the value sits. Overlap across the retailers I track held at just under 50%, so roughly half of all listed stones appear at more than one seller.

Radiant cuts were the standout shape mover this week, with median new listing prices climbing 50% to $1,593. That's a meaningful jump on solid volume (nearly 55,000 new radiants listed). Asscher cuts went the other direction, with median prices falling 28.7% to $1,770. Part of that reflects the wild range on larger lab-grown asschers currently in the market; three 37.34ct stones appeared priced anywhere from $23,800 to $158,200 for what look like identical specs. Rounds continued to dominate new supply at 42.5% of all listings, with a median price of $830. Hearts slipped about 9.5% on price to $1,751.

At the top end, a 15.63ct E Flawless natural pear listed at $2.33 million led the week's most expensive stones. A 1.24ct fancy colour natural pear came in at $1.45 million, a reminder that colour diamonds operate on their own pricing logic entirely. On the lab-grown side, a 50.29ct cushion appeared at $95,140, which works out to under $1,900 per carat for a stone north of 50 carats.

New listing flow is slowing. Removals have essentially stalled. Inventory is accumulating and spreads are widening. If you're buying in this market, the range of prices for any given stone is as wide as it's been, and that works in your favour if you're willing to compare. I'll be watching whether removal volumes recover next week or whether this buildup continues into late May.

Diamond Market Charts, Week 20, 2026 (11 to 18 May 2026)

The five charts below summarise what the diamond market did during 11 to 18 May 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 19, 2026

Biggest shape movers

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.