In May 2021, Pandora—the world’s largest jewelry company—announced that it will no longer sell mined diamonds. Instead, the company is offering only synthetic diamonds, created in laboratories. The artificial stones are cheaper to produce, and they avoid the environmental impacts of mining, the company says.

Natural diamonds form when the element carbon (C) is exposed to the intense heat and pressure of Earth’s interior. Synthetic diamonds are created by replicating these same forces using machines. The lab-grown gems are chemically and physically identical to natural diamonds, says Wendy Mao, a geologist at Stanford University in California. And synthetic diamonds take only a few months, instead of billions of years, to create.