The collapse is driven by the rise of reactor-grown diamonds in China and a 96% crash in wholesale synthetic prices, which have fallen to about $100 a carat. This price erosion is evident at the retail level, where Walmart sells half-carat lab-grown diamond earrings for $12. Data from The Knot shows that 61% of engagement rings sold in 2025 featured lab-grown center stones, up 239% since 2020, while De Beers' own average selling price dropped 32% in one year to $105 a carat.
