By Isabella O'Malley
(fortune.com) - The muted sounds of hammering and sanding drift down to the first floor of Bario Neal, a jewelry store in Philadelphia, where rustic artwork that mimics nature hangs on warmly-lit walls. In the U.S., lab-grown diamond sales jumped 16% in 2023 from 2022, according to Edahn Golan, an industry analyst. They cost a fraction of the stones formed naturally underground.