Blood Diamond star (and notorious playboy) Leonardo DiCaprio probably won’t offer his latest model girlfriend an engagement ring anytime soon. But that hasn’t kept the actor and environmental activist from investing in Diamond Foundry, one of several lab-grown gem companies attempting to disrupt the controversial diamond-mining industry.

Diamond Foundry and its competitors, including Brilliant Earth and Pure Grown Diamonds, use technology that has been around since the mid-20th century to manufacture clear and colored diamonds that are chemically and physically identical to mined diamonds.

The How

Lab-grown diamonds were created in the 1950s by General Electric scientists, who forged them out of heated and pressurized graphite. They could produce only small impure stones for industrial uses like drills and blades. But today a more refined process called chemical vapor deposition (CVD) “grows” diamonds as clear and nearly as large as those dug up. Technicians start with a tiny diamond seed that they place in a vacuum-sealed chamber. The seed is enveloped in a cloud of carbon gas that’s heated to more than 1,800 degrees Fahrenheit. The carbon that crystallizes on the seed grows it. Cutters then shape the lab stone in the same way they would a mined diamond.

If you buy a lab-grown diamond, only you and the seller will know it isn’t “real”; manmade diamonds are actual diamond material (crystallized carbon). The terms “real” or “synthetic” aren’t actually fair to manufacturers, as many buyers consider them synonymous with “imitation.” In the U.S., the Federal Trade Commission prevents sellers from referring to lab-grown diamonds as synthetic because other terms (such as “laboratory-grown” or “laboratory-created”) “would more clearly communicate the nature of the stone.”

The Why

Should you disregard industry giant De Beers’ “A Diamond is Forever” slogan and pony up for a stone that took days to hatch in a lab, rather than millennia to grow in the ground?

The reasons to go faux include price as well as human and environmental ethics. As Leo’s Blood Diamond gem-hunting character learns, the diamond business in Africa is fraught with child labor, violence, and environment-destroying mining methods. Although the industry is trying to keep conflict and blood diamonds from entering the market, it has been only marginally successful. Choosing a lab-grown rock assures that your purchase is free of ties to human-rights or natural-resources exploitation.

You’ll also save big by opting for a lab stone—they’re priced about 20 to 30 percent less than mined diamonds. Prices are also significantly reduced for fancy colors, which are rare in nature but comparably easy to grow in a lab.