Gen Z and millennials proudly wear 'lab-grown' diamonds, oblivious to the fact they're made from burning coal in China and India

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. Waiting for one of those rings is Haley Farlow, a 28-year-old second grade teacher who has been designing her three-stone engagement ring with her boyfriend. They care about price and also don’t want jewelry that takes a toll on the Earth, or exploits people in mining. So they’re planning on buying diamonds grown in a laboratory. “Most of my...