Lab-grown diamonds have a strong pull for consumers who care about sustainability and ethical sourcing. Photo: Vrai. How would you feel about giving, or receiving, a 4-carat engagement ring?

Scientists have used a new technique to synthesize diamonds at normal, atmospheric pressure and without a starter gem, which could make the precious gemstones easier to grow in the lab.

Lab-grown diamonds are expected to make up 21% of all diamonds sold this year, according to data from Statista. Jesse De Leon has been on the front lines at Liori Diamonds , based in New York City.

Mr. Cuadros is the author of “When We Sold God’s Eye: Diamonds, Murder, and a Clash of Worlds in the Amazon.” In the lead-up to Valentine’s Day, people across the world rush to buy diamond ...

Diamonds Unearthed In the first installment of a multi-part series, Smithsonian diamond expert Jeffrey Post explains how the rare crystals form ...