Diamond is the hardest and most scratch-resistant material used widely by humanity.1 Besides a number of uses in industry, diamond gems are also very popular for use in jewellery, reaching nearly $100 billion in estimated global sales in 2024.2 Until very recently, the only sources of gem-quality diamonds were mines. But technological advances in producing diamonds from common graphite using machines have introduced, for the first time in history, a viable and much cheaper alternative source. From 2015 to 2025, the prices of these “lab-grown” diamonds fell by nearly 90%.3 Diamond gemstones in general have seen a rapid collapse in prices since 2022 and the status of diamonds as a rare luxury item has thus become threatened.4 In 2024, for the first time, a majority (52%) of American couples purchased an engagement ring with a “lab-grown” diamond rather than a mined diamond.5 As recently as 2019, the figure was just 12%.6