Will Lab Diamond Prices Keep Falling? The 2026 Price Floor

Roughly 74 percent since 2020. That figure comes from Edahn Golan Diamond Research and is corroborated by Draco Price Trend data. The scale of the collapse is easiest to see in one stone. A 1 carat lab diamond averaged 3,410 USD per carat in 2020. By May 2026, StoneAlgo put the average at 564 USD. Six years. One sixth of the price.

The wholesale side fell even harder. De Beers said lab grown wholesale jewelry prices dropped about 90 percent. Its own Lightbox brand launched at 800 USD per carat and closed on May 9, 2025. A finished lab stone now costs 80 to 90 percent less than its mined equivalent, per BriteCo.

Buyers noticed. Lab grown now accounts for more than 45 percent of US engagement rings, per 2025 to 2026 industry data. The collapse in price built the category. The question for anyone shopping in 2026 is whether the collapse continues.

The steep phase is over for certified quality. Three independent signals point the same direction.

First, the rate of decline. StoneAlgo's May 2026 data shows a year over year decline of 2.59 percent. Compare that to a 74 percent fall across the prior six years. The curve has gone nearly flat.

Second, the quarterly pattern. 2026 shows the smallest quarterly declines in two years. Not one soft quarter. A sustained flattening.

Third, the cost structure. Premium certified stones have hit a production cost floor. Growing, cutting, and certifying a high grade stone has a real cost. Prices cannot fall below it for long.

Here is where the market sat in May 2026, per StoneAlgo.

It means the seller of last resort has named the floor. De Beers described lab grown wholesale prices as tracking toward cost plus. Those are their words.

Cost plus is what a commodity looks like at the bottom. Production cost, plus a thin margin, and nothing else. When the industry's most powerful incumbent says prices are converging on cost, it is telling you the fall has a hard stop.

De Beers has already acted on that logic. It launched Lightbox at 800 USD per carat to anchor lab grown as cheap fashion product. It closed Lightbox on May 9, 2025. You do not shut a price weapon while prices still have far to fall. You shut it when the war is over. The full account of that retreat is in the lab diamond price collapse report.

For a premium certified stone, waiting has stopped paying. A 2.59 percent year over year decline on a 1 carat average of 564 USD is a rounding error, not a windfall.

Split the market in two and the answer gets sharper. Commodity grade stones, the uncertified and lower grade material that makes up most production, may drift lower. They sit closest to raw production economics. Premium certified stones, the IGI graded, high color, high clarity segment, have stabilized at their production cost floor.

GIA's October 1, 2025 decision reinforced that split. It stopped applying 4Cs nomenclature to lab grown stones, replacing it with premium and standard tiers, and noted that more than 95 percent of lab grown stones fall in one narrow color and clarity band. Certification now does the work of separating the stabilized premium segment from the drifting commodity one.

Two honest caveats. First, nothing here is a forecast of the exact bottom. It is a description of a curve that has already flattened. Second, a lab diamond is not an investment. Lab grown typically recovers 20 to 40 percent of purchase price at resale, against 50 to 60 percent for natural, per 2026 market analyses. Buy for beauty and size. The floor argument is about not overpaying by waiting, not about appreciation.

It changes the buyer's math from timing to selection. Between 2020 and 2025, patience was a strategy. The same budget bought a visibly larger or better stone every year. In 2026, with premium certified prices at their cost floor, the gains from waiting have compressed to low single digits.

The leverage now sits in what you buy, not when. At May 2026 StoneAlgo averages, the jump from 1 carat at 564 USD to 3 carats at 1,865 USD costs less than a single carat did in 2020. Size, certification, and setting quality are where a 2026 budget works hardest. For finished pieces, the same logic routes to the under $2,000 collection, where the certified floor now sits.

Methodology note. Draco Diamond's Price Trend Report tracks per carat lab diamond prices from 2020 to 2026 and records a decline of roughly 74 percent, corroborating Edahn Golan Diamond Research. Retail averages cited are StoneAlgo, May 2026, in USD. Draco's catalog is IGI certified E to F color VS2 and better, and the brand holds a 4.8 out of 5 rating across 864 verified reviews.