The lab-grown price collapse refers to the sustained, large-magnitude decline in retail and wholesale prices for synthetic diamond between 2018 and the mid-2020s, driven by rapid expansion of growth capacity and the failure of the trade to defend established price points. The collapse is the dominant economic fact of the lab-grown jewellery category and has structural implications for the wider gem trade.

The numbers

Wholesale price tracking from IDEX, Rapaport and the Mercury Index records broadly consistent findings. Wholesale prices for one-carat F VS round brilliant lab-grown diamonds fell from roughly 2500 to 3000 dollars in 2018 to under 800 dollars by 2023, a decline on the order of seventy to eighty percent. Larger sizes fell proportionally further: three-carat lab-grown rounds in commercial qualities fell from above 10000 dollars wholesale in 2018 to under 2000 dollars by 2024. Retail prices, which carry markup over wholesale, followed the same direction with somewhat smaller percentage declines depending on retailer category.

The decline was steeper in larger sizes and in CVD-grown material than in HPHT, reflecting the relative cost reductions in CVD reactor technology and yield. The decline was steeper in commercial qualities (G to J colour, VS2 to SI clarity) than in highest qualities (D to F, IF to VVS), since the upper qualities continue to carry production cost premiums and represent a smaller share of total output.

Causes

Three causes are commonly cited. First, growth capacity expansion. CVD reactor counts in India increased by an order of magnitude over the 2019-2023 period, with capital costs per chamber falling and growth times shortening as engineering improved. Second, vertical disintegration. The lab-grown industry, unlike the historical natural diamond industry, lacks the centralised producer cartel that disciplined supply for decades. With many producers, no marketing federation, and online price-discovery, prices fell to marginal cost more rapidly. Third, the absence of an organised inventory holdback. Producers grew on demand and sold on demand, with limited willingness or capability to hold rough off the market.

de Beers's Lightbox launch in 2018, with its 800-dollar-per-carat fixed retail price, is sometimes cited as an additional cause, with the strategic argument that a major industry player had effectively endorsed a low price point. Lightbox's closure in 2024 supports an alternative reading, in which Lightbox was already at the wrong price point by mid-cycle and could not adjust without abandoning its model.

Coloured stones

Synthetic coloured stones, including ruby, sapphire and emerald, have not seen a comparable price collapse. The wholesale price of synthetic ruby (Verneuil flame-fusion, flux-grown, hydrothermal) has been low for decades and has not changed dramatically. The natural coloured-stone market does not have a high-volume mass-market segment for the synthetic side to undercut in the way that lab-grown diamond undercut natural diamond mid-market. Synthetic emerald and synthetic alexandrite likewise have not undergone a price collapse, since the markets for them were never structured around defended high prices.

Effects on the trade

For the lab-grown category, the price collapse has compressed margins and increased competitive pressure on retailers. For the natural-diamond category, it has created a sharp visible price gap that retailers must navigate. For the consumer, it has lowered entry-price points dramatically but raised concerns about purchase remorse, since stones bought in 2018 at 2018 prices are dramatically less valuable in 2024 dollars than they would otherwise have been.

The price collapse has also forced the trade to confront the difference between price and value in the diamond category. Mined diamond has historically traded as a luxury good with significant brand and rarity premium; lab-grown diamond is increasingly trading closer to its production cost. The two categories are converging on different equilibria, and the gap between them is the principal subject of the lab-grown vs natural debate.

Outlook

Whether the price collapse has reached a floor or whether it will continue is contested. Production costs continue to fall, suggesting further price decline is technically possible. Some producers have exited the market, suggesting consolidation that could stabilise prices. Brand-led retailers continue to defend higher price points than commodity retailers. The overall direction of the next several years remains uncertain, but a return to 2018 price levels is no longer a credible scenario.

Implications for the wider gem market

The lab-grown price collapse has not, on the available evidence, produced a comparable collapse in natural diamond prices. The two categories have diverged in both price level and consumer positioning, with natural diamond holding much of its established value while lab-grown has fallen sharply. This divergence is itself notable. Whether it will hold over a longer horizon, or whether the natural side will eventually feel pressure from the gap, is the central open question facing the gem trade in the latter half of the 2020s.