Diamond Market, Week 2, 2026

The round brilliant's median new-listing price dropped to $900 this week, down 41% from $1,525 in week 1. That's a striking move on the market's highest-volume shape, one that accounted for 37.6% of all new listings (283,162 stones). A drop that sharp, that fast, on that much volume isn't noise. It reflects a flood of lower-priced lab-grown rounds entering the market as the post-holiday listing cycle kicks in, and it pulls the overall median price down even as per-carat figures edge slightly higher.

Total new listings fell 31% week on week, from 1,088,559 to 752,238, and off-market activity followed a similar path down, dropping 27% to 325,375. That's a calmer week by any measure. But active inventory still grew to 9.61 million stones, up 4.65% on last week, and total inventory value pushed past $30.4 billion, a gain of nearly $1.4 billion. Fewer listings came in, fewer went off, yet the pool expanded. A handful of names did most of the listing, with the top five retailers accounting for 78.6% of new additions.

Lab-grown's share of active inventory nudged above 60% for the first time in this data set, sitting at 60.1% versus 59.5% last week. More telling is what happened to lab-grown median prices among new listings: down 33% to $1,077.72. Natural diamonds held more steadily, their new-listing median slipping just under 4% to $1,257.30, while their per-carat figure actually rose 4.5% to $2,526.32. The gap between natural and lab-grown per carat now sits at roughly 2.2 to 1. That ratio is worth watching as lab supply keeps climbing.

The Asscher had a genuinely significant week. Its median new-listing price jumped 41.5% to $2,660, on nearly 20,000 new listings, which is a real volume of product. Heart shapes also moved up sharply, gaining 22.9% to reach $1,854.31. These aren't categories that usually lead the week, so the combination of price and volume in Asscher is notable. Whether it reflects a mix shift toward larger, natural stones in that cut or simply a change in which retailers pushed inventory this week, I'd want to see it hold in week 3 before calling it a trend.

The cross-retailer spread narrowed marginally, from 64.4% to 63.7%. Still wide. A buyer looking at the same stone across the retailers I track can expect to see price spreads of that magnitude, which means comparison shopping still pays off substantially. The most expensive stone in the period was a natural 25-carat D Flawless emerald cut certified by GIA, listed at $3,128,547. On the other end of the size story, the largest stone was a 40-carat lab-grown G VS2 oval at $106,710, about $2,663 per carat. The contrast between those two extremes says a lot about where the two markets sit right now.

Going into week 3, the round price is the thing to watch. A one-week correction in new-listing mix is one thing; if the $900 median holds or falls further, it will start dragging the whole market's per-carat averages down with it. The Asscher strength and the lab-grown share crossing 60% are both worth tracking. If lab-grown supply keeps accelerating while prices compress, the per-carat gap with natural widens further, and that's the kind of structural shift that takes months to play out.

Diamond Market Charts, Week 2, 2026 (5 to 12 January 2026)

The five charts below summarise what the diamond market did during 5 to 12 January 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 1, 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.