Expect the collapse in diamond prices to accelerate substantially over the next few years. The natural-diamond market is shrinking in both size and value and circling the drain following the commoditisation of its product by modern technology. The same thing happened to pearls 100 years ago, but it will be much worse for diamonds: they will become a signal of bad taste rather than wealth, just as pearls went from high society to a matronly cliché within 50 years. I have been telling friends in the diamond industry to find a new line of work for ten years. It was clearly only a matter of time before lab-grown diamonds became a mass-market commodity, sold at some small premium over production costs—which would themselves continue to plummet. Since they are identical to natural diamonds, and buyers actually have multiple reasons to choose them instead—no “blood diamonds” and supposedly greater environmental friendliness—most buyers will not care. Attempts to differentiate the products using $20,000 machines will not help: they are indistinguishable in real life. There was always going to be some multiple that people would be willing to pay for “natural” over “lab,” but it did not really matter whether that multiple was 2× or 10×. Once lab-grown diamonds can be made for next to nothing, even ten times next to nothing is still very little. People will pay more—perhaps much more—for an identical product because of its backstory, but not infinitely more. The reason natural-diamond prices have held up reasonably well over the past four years—“only” falling by around 50% in real terms—has more to do with supply cutbacks. Production has been reduced by about 20% over that period, from 120 million to 98 million carats, in a desperate attempt to support prices as the natural and lab-grown markets diverge. If production returned to its previous level, prices would fall even faster. But it is going to get much, much worse. A trip to Miami will explain why: people who look like gangsters walk around wearing enormous tennis bracelets that would have cost a million dollars 20 years ago but can now be purchased for the price of a used Rolex. Diamonds are going to become a sign of tackiness—as, frankly, they always should have been—rather than class or exclusivity. And then the game will be up for everyone in the diamond industry.