[tt] diamonds on demand

[Eugen Leitl]

http://www.smithsonianmag.com/science-nature/diamonds-on-demand.html

Diamonds on Demand

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

    * By Ulrich Boser 
    * Photographs by Max Aguilera-Hellweg 
    * Smithsonian magazine, June 2008

I'm 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.

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. 

Credit for the modern cult of the diamond goes primarily to South
Africa-based De Beers, the world's largest diamond producer. Before the
1940s, diamond rings were rarely given as engagement gifts. But De Beers'
marketing campaigns established the idea that the gems are the supreme token
of love and affection. Their "A Diamond Is Forever" slogan, first deployed in
1948, is considered one of the most successful advertising campaigns of all
time. Through a near total control of supply, De Beers held almost complete
power over the diamond market for decades, carefully hoarding the gemstones
to keep prices—and profits—high. While the company has lost some of its power
to competitors in Canada and Australia over the past few years, it still
controls almost two-thirds of the world's rough diamonds.

Diamond growers are proud of the challenge they pose to De Beers and the rest
of the natural diamond industry. Apollo's slogan is "A Diamond Is for
Everyone." So far, though, Apollo's colorless gems cost about the same as
natural stones, while the company's pink, blue, champagne, mocha and brown
diamonds retail for about 15 percent less than natural stones with such
colors, which are very rare and more expensive than white diamonds.
Meanwhile, consumers may well be receptive to high-quality,
laboratory-produced diamonds. Like most open-pit mines, diamond mines cause
erosion, water pollution and habitat loss for wildlife. Even more troubling,
African warlords have used diamond caches to buy arms and fund rebel
movements, as dramatized in the 2006 movie Blood Diamond. Actor Terrence
Howard wears a diamond lapel pin with Apollo stones. He told reporters,
"Nobody was harmed in the process of making it."

Half a dozen other companies have begun to manufacture gem-quality diamonds
using not CVD but a process that more closely mimics the way diamonds are
created in the earth. The method—basically an improvement on how scientists
have been making diamonds since the 1950s—requires heat of more than 2,000
degrees and pressure 50 times greater than that at the surface of the earth.
(Both the heat and pressure are more than what CVD requires.) The washing
machine-size devices can't produce stones much larger than six carats. These
HPHT diamonds—the initials stand for high pressure and high temperature—have
more nitrogen in them than CVD diamonds do; the nitrogen turns the diamonds
amber-colored. For now, though, the process has a significant benefit over
CVD: it's less expensive. While a natural, one-carat amber-colored diamond
might retail for $20,000 or more, the Florida-based manufacturer Gemesis
sells a one-carat stone for about $6,000. But no one, Gemesis included, wants
to sell diamonds too cheaply lest the market for them collapse.

Gemologists plying everyday tools can seldom distinguish between natural and
lab-grown diamonds. (Fake diamonds such as cubic zirconia are easy to spot.)
De Beers sells two machines that detect either chemical or structural
characteristics that sometimes vary between the two types of stones, but
neither machine can tell the difference all the time. Another way to identify
a lab-produced diamond is to cool the stone in liquid nitrogen and then fire
a laser at it and examine how the light passes through the stone. But
equipment is expensive and the process can take hours.

Diamonds from Apollo and Gemesis, the two largest manufacturers, are marked
with a laser-inscribed insignia visible with a jeweler's loupe. Last year,
the Gemological Institute of America, an industry research group, began to
grade lab-grown stones according to carat, cut, color and clarity—just as it
does for natural stones—and it provides a certificate for each gem that
identifies it as lab grown.

The diamond-mining companies have been fighting back, arguing that all that
glitters is not diamond. De Beers' ads and its Web sites insist that diamonds
should be natural, unprocessed and millions of years old. "Diamonds are rare
and special things with an inherent value that does not exist in factory-made
synthetics," says spokeswoman Lynette Gould. "When people want to celebrate a
unique relationship they want a unique diamond, not a three-day-old
factory-made stone." (De Beers does have an investment in Element Six, the
company that makes thin industrial diamonds.)

The Jewelers Vigilance Committee (JVC), a trade group, has been lobbying the
Federal Trade Commission to prevent diamond manufacturers from calling their
stones "cultured," a term used for most of the pearls sold today. (People in
the mined diamond business use less-flattering terms such as "synthetic.")
The JVC filed a petition with the agency in 2006, claiming that consumers are
often confused by the nomenclature surrounding lab-grown diamonds.