Between 2018 and 2024, retail and wholesale prices for lab-grown diamond fell by amounts widely reported in the trade press at seventy to ninety percent depending on size and quality. The collapse is one of the largest and fastest price declines on record for any category of finished jewellery good and is a defining feature of the diamond market of the early 2020s.

The starting point

In 2018, when de Beers launched Lightbox at a fixed retail price of 800 dollars per carat, the wholesale market for natural-equivalent lab-grown rounds was running at roughly twenty to thirty percent below comparable natural diamond, with one-carat F VS round brilliants in the high three thousands at retail. Lightbox's flat pricing was widely interpreted by the trade as a strategic effort to disrupt that hierarchy, but for the first year or two it appeared simply as one option in a wider market.

The decline

Two factors drove the subsequent collapse. First, growth capacity expanded dramatically. CVD reactor counts in India and China rose by an order of magnitude between 2019 and 2023, and unit growth times for typical commercial sizes fell as chamber and process engineering matured. The marginal cost of a one-carat CVD diamond of commercial colour and clarity, by trade estimates, fell from above 600 dollars in 2018 to below 100 dollars by 2023.

Second, retail differentiation proved hard to sustain. Lab-grown stones sold next to natural stones in the same showcase, often on the same display tray, made the price gap visible and the choice explicit. Online retailers used the gap as their core marketing message; James Allen, Brilliant Earth and the natural-equivalent programmes of the major chains all carried lab-grown alongside natural by 2021.

Wholesale pricing followed the cost curve down. By 2023, IDEX and Rapaport tracking showed one-carat G VS2 lab-grown rounds in the high three figures at wholesale, with retail commonly under 1500 dollars. Larger sizes fell proportionally further, and three-carat-plus stones, which had still commanded meaningful premiums in 2020, were offered at thirty cents on the natural-diamond dollar by 2024.

Effect on the trade

For the lab-grown specialist retailer the collapse compressed margin sharply. For the integrated retailer carrying both lab-grown and natural, the lab-grown line subsidised store traffic and supported entry-price points but contributed less to gross profit. Resale value, never high, became negligible, since a buyer of a 2020 stone seeking to trade it back in 2024 was offered a fraction of a fraction of original retail, with the resale market discussed in the entry on lab-grown diamond ring resale.

The natural diamond trade reacted with renewed messaging emphasising rarity, store of value and provenance. Whether the price decline has stabilised at a new floor or will continue to track the falling marginal cost of growth remains an open question.