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These rocks don’t lose their shape: thanks to recent advances, scientists can grow gems (from Apollo) and industrial diamonds in a matter of days. (Max Aguilera-Hellweg)

Diamonds on Demand

Lab-grown gemstones are now practically indistinguishable from mined diamonds. Scientists and engineers see a world of possibilities

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I am sitting in a fast-food restaurant outside Boston that, because of a nondisclosure agreement I had to sign, I am not allowed to name. I'm waiting to visit Apollo Diamond, a company about as secretive as a Soviet-era spy agency. Its address isn't published. The public relations staff wouldn't give me directions. Instead, an Apollo representative picks me up at this exurban strip mall and drives me in her black luxury car whose make I am not allowed to name along roads that I am not allowed to describe as twisty, not that they necessarily were.

"This is a virtual diamond mine," says Apollo CEO Bryant Linares when I arrive at the company's secret location, where diamonds are made. "If we were in Africa, we'd have barbed wire, security guards and watch towers. We can't do that in Massachusetts." Apollo's directors worry about theft, corporate spies and their own safety. When Linares was at a diamond conference a few years ago, he says, a man he declines to describe slipped behind him as he was walking out of a hotel meeting room and said someone from a natural diamond company just might put a bullet in his head. "It was a scary moment," Linares recalls.

Bryant's father, Robert Linares, working with a collaborator who became a co-founder of Apollo, invented the company's diamond-growing technique. Robert escorts me into one of the company's production rooms, a long hall filled with four refrigerator-size chambers bristling with tubes and gauges. As technicians walk past in scrubs and lab coats, I glance inside the porthole window of one of the machines. A kryptonite-green cloud fills the top of the chamber; at the bottom are 16 button-size disks, each one glowing a hazy pink. "Doesn't look like anything, right?" Robert says. "But they will be half-caraters in a few weeks."

In 1796, chemist Smithson Tennant discovered that diamond is made out of carbon. But only since the 1950s have scientists managed to produce diamonds, forging them out of graphite subjected to temperatures as high as 2,550 degrees Fahrenheit and pressures 55,000 times greater than that of earth's atmosphere. But the stones were small and impure. Only the grit was useful, mostly for industrial applications such as dental drills and hacksaw blades. Over the past decade, however, researchers such as Linares have perfected a chemical process that grows diamonds as pure and nearly as big as the finest specimens hauled out of the ground. The process, chemical vapor deposition (CVD), passes a carbon gas cloud over diamond seeds in a vacuum chamber heated to more than 1,800 degrees. A diamond grows as carbon crystallizes on top of the seed.

Robert Linares has been at the forefront of crystal synthesis research since he started working at Bell Labs in Murray Hill, New Jersey, in 1958. He went on to start a semiconductor company, Spectrum Technologies, which he later sold, using the proceeds to bankroll further research on diamonds. In 1996, after nearly a decade working in the garage of his Boston home—no kidding, in the garage, where he'd set up equipment he declines to describe—he discovered the precise mixture of gases and temperatures that allowed him to create large single-crystal diamonds, the kind that are cut into gemstones. "It was quite a thrill," he says. "Like looking into a diamond mine."

Seeking an unbiased assessment of the quality of these laboratory diamonds, I asked Bryant Linares to let me borrow an Apollo stone. The next day, I place the .38 carat, princess-cut stone in front of Virgil Ghita in Ghita's narrow jewelry store in downtown Boston. With a pair of tweezers, he brings the diamond up to his right eye and studies it with a jeweler's loupe, slowly turning the gem in the mote-filled afternoon sun. "Nice stone, excellent color. I don't see any imperfections," he says. "Where did you get it?"

"It was grown in a lab about 20 miles from here," I reply.

He lowers the loupe and looks at me for a moment. Then he studies the stone again, pursing his brow. He sighs. "There's no way to tell that it's lab-created."

More than one billion years ago, and at least 100 miles below the surface of the earth, a mix of tremendous heat and titanic pressure forged carbon into the diamonds that are mined today. The stones were brought toward the surface of the earth by ancient underground volcanoes. Each volcano left a carrot-shaped pipe of rock called kimberlite, which is studded with diamonds, garnets and other gems. The last known eruption of kimberlite to the surface of the earth happened 47 million years ago.

Diamonds have been extracted from almost every region of the world, from north of the Arctic Circle to the tropics of western Australia. Most diamond mines start with a wide pit; if the kimberlite pipe has a lot of diamonds, miners dig shafts 3,000 feet or more deep. In areas where rivers once ran over kimberlite seams, people sift diamonds from gravel. Loose diamonds used to turn up in fields in the Midwest in the 1800s; they were deposited there by glaciers. Most geologists believe that new diamonds continue to form in the earth's mantle—much too deep for miners to reach.

The word "diamond" comes from the ancient Greek adamas, meaning invincible. People in India have mined diamond gems for well over 2,000 years, and first-century Romans used the stones to carve cameos. Over the ages, diamonds acquired a mystique as symbols of wealth and power. During the 16th century, the Koh-i-Noor, a 109-carat diamond from the Kollur mine in southern India, was perhaps the most prized item on the Indian subcontinent. Legend held that whoever owned it would rule the globe. "It is so precious," noted a writer at the time, "that a judge of diamonds valued it at half the daily expense of the whole world." Great Britain got the stone in 1849 when Lahore and Punjab became part of the British Empire; the diamond now sits in the Tower of London, the centerpiece of a crown made for Queen Elizabeth in 1937.

And yet diamonds are simply crystallized pure carbon, just as rock candy is crystallized sugar—an ordered array of atoms or molecules. Another form of pure carbon is graphite, but its atoms are held together in sheets rather than rigidly attached in a crystal, so the carbon sloughs off easily, say, at the tip of a pencil. Thanks to the strength of the bonds between its carbon atoms, diamond has exceptional physical properties. It's the hardest known material, of course, and it doesn't react chemically with other substances. Moreover, it's fully transparent to many wavelengths of light, is an excellent electrical insulator and semiconductor, and can be tweaked to hold an electrical charge.

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