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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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(Continued from page 1)

It's because of these admittedly unglamorous properties that lab-produced diamonds have the potential to dramatically change technology, perhaps becoming as significant as steel or silicon in electronics and computing. The stones are already being used in loudspeakers (their stiffness makes for an excellent tweeter), cosmetic skin exfoliants (tiny diamond grains act as very sharp scalpels) and in high-end cutting tools for granite and marble (a diamond can cut any other substance). With a cheap, ready supply of diamonds, engineers hope to make everything from higher-powered lasers to more durable power grids. They foresee razor-thin computers, wristwatch-size cellphones and digital recording devices that would let you hold thousands of movies in the palm of your hand. "People associate the word diamond with something singular, a stone or a gem," says Jim Davidson, an electrical engineering professor at Vanderbilt University in Tennessee. "But the real utility is going to be the fact that you can deposit diamond as a layer, making possible mass production and having implications for every technology in electronics."

At the U.S. Naval Research Lab, a heavily guarded compound just south of the U.S. Capitol, James Butler leads the CVD program. He wears a gold pinky ring that sparkles with one white, one green and one red diamond gemstone, all of them either created or modified in a lab. "The technology is now at a point that we can grow a more perfect diamond than we can find in nature," he says.

Butler, a chemist, pulls from his desk a metal box that brims with diamonds. Some are small, square and yellowish; others are round and transparent disks. He removes one wafer the size of a tea saucer. It's no thicker than a potato chip and sparkles under the fluorescent light. "That's solid diamond," he says. "You could use something like this as a window in a space shuttle."

The military is interested in lab-grown diamonds for a number of applications, only some of which Butler is willing to discuss, such as lasers and wearproof coatings. Because diamond itself doesn't react with other substances, scientists think it's ideal for a biological weapons detector, in which a tiny, electrically charged diamond plate would hold receptor molecules that recognize particular pathogens such as anthrax; when a pathogen binds to a receptor, a signal is triggered. Butler, working with University of Wisconsin chemist Robert Hamers, has produced a prototype of the sensor that can detect DNA or proteins.

The largest single-crystal diamond ever grown in a lab is about .7 inches by .2 inches by .2 inches, or 15 carats. The stone isn't under military guard or at a hidden location. It's in a room crowded with gauges and microscopes, along with the odd bicycle and congo drum, on a leafy campus surrounded by Washington, D.C.'s Rock Creek Park. Russell Hemley, director of the Carnegie Institution's Geophysical Lab, started working on growing diamonds with CVD in 1995. He pulls a diamond out of his khakis. It would be hard to mistake this diamond for anything sold at Tiffany. The rectangular stone looks like a thick piece of tinted glass.

Hemley and other scientists are using laboratory and natural diamonds to understand what happens to materials under very high pressure—the type of pressure at the center of the earth. He conducts experiments by squeezing materials in a "diamond anvil cell," essentially a powerful vise with diamonds at both tips.

A few years ago, Hemley created one of the hardest known diamonds. He grew it in the lab and then placed it in a high-pressure, high-temperature furnace that changed the diamond's atomic structure. The stone was so hard that it broke Hemley's hardness gauge, which was itself made out of diamond. Using the super-hard diamond anvil, Hemley has increased the amount of pressure he can exert on materials in his experiments up to four million to five million times greater than atmospheric pressure at sea level.

"Under extreme conditions, the behavior of materials is very different," he explains. "Pressure makes all materials undergo transformations. It makes gases into superconductors, makes novel super-hard materials. You can change the nature of elements."

He discovered, for instance, that under pressure, hydrogen gas merges with iron crystals. Hemley believes that hydrogen might make up a portion of the earth's core, which is otherwise composed largely of iron and nickel. He has been studying the hydrogen-iron substance to understand the temperature and composition of the center of our planet.

In another surprising discovery, Hemley found that two common bacteria, including the intestinal microorganism E. coli, can survive under colossal pressure. He and his colleagues placed the organisms in water and then ratcheted up the diamond anvil. The water solution soon turned into a dense form of ice. Nevertheless, about 1 percent of the bacteria survived, with some bacteria even skittering around. Hemley says the research is more evidence that life as we know it may be capable of existing on other planets within our solar system, such as under the crust of one of Jupiter's moons. "Can there be life in deep oceans in outer satellites like Europa?" asks Hemley. "I don't know, but we might want to be looking."

Hemley hopes to soon surpass his own record for the largest lab-grown diamond crystal. It's not clear who has produced the largest multiple-crystal diamond, but a company called Element Six can make wafers up to eight inches wide. The largest mined diamond, called the Cullinan diamond, was more than 3,000 carats—about 1.3 pounds—before being cut. The largest diamond so far found in the universe is the size of a small planet and located 50 light-years away in the constellation Centaurus. Astronomers with the Harvard-Smithsonian Center for Astrophysics discovered the gigantic stone a few years ago, and they believe the 2,500-mile-wide diamond once served as the heart of a star. It's ten billion trillion trillion carats. The astronomers named it Lucy in honor of the Beatles' song "Lucy in the Sky With Diamonds."

Natural diamonds aren't particularly rare. In 2006, more than 75,000 pounds were produced worldwide. A diamond is a precious commodity because everyone thinks it's a precious commodity, the geological equivalent of a bouquet of red roses, elegant and alluring, a symbol of romance, but ultimately pretty ordinary.

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