Diamonds are forever, but De Beers’ vow to never sell diamonds made in labs didn’t last as long.

Rather than selling real stones that have been formed underground over billions of years, the world’s biggest diamond miner is backtracking on its promise.

They will start selling synthetic stones for about R10 000 a carat under a new Lightbox Jewellery brand kicking off the U.S. later this year, according to a memo sent out to their customers.

So what made the folks at De Beers change their tune?

The reason is not that surprising, Fortune reports:

While man-made gems make up just a fraction of the R1 trillion 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.

Makes sense. It’s not easy to put a ring on it without splurging thousands of rands.

And it’s not like De Beers haven’t tried their hand at making synthetic diamonds before. They’ve got a unit called Element Six unit, which is the top dog in the synthetic diamond-making game.

Their purpose? By producing the man-made diamonds, it then helps tell the difference between natural and man-made types, which reassures consumers that they’re buying the real thing.

At least it sounds a lot better than growing your own diamonds.

[source:fortune]