The world’s biggest diamond miner for years vowed that it wouldn’t sell stones made in laboratories. Now, it has U-turned on that pledge and will start selling man-made stones for about $800 a carat, according to a memo sent to its customers and obtained by Bloomberg News.

While De Beers has never sold man-made diamonds before, it’s very good at making them. The company’s Element Six unit is one of the world’s leading companies for synthetic diamonds, which are mostly used for industrial purposes. It has also been producing gem-quality stones for years to help it tell the difference between natural and man-made types and to reassure consumers that they’re buying the real thing.

While man-made gems make up just a fraction of the $80 billion global diamond market, demand is increasing as buyers look for stones that are cheaper. Retailers like Walmart Inc. have sold synthetic diamonds to customers seeking cheaper alternatives.

De Beers, a unit of Anglo American Plc (AAUKY), will sell the lab-produced gems under a new Lightbox Jewelry brand to be started in the U.S. later this year, according to the memo.