Gem Quality Synthetic Diamonds
Recently, new methods for the creation of synthetic
stones have been developed. Both of these methods can grow large
quality stones. This development is shaking the earth in Antwerp
, Belgium (where most diamond
trades are handled), and is greatly feared by the De Beers
. The stones produced are actual diamonds, nearly identical to their mined counterparts, and visually indistinguisable from natural gems.
There are two methods for producing gem quality stones. One, created in Russia
an developed by a Florida
based company called Gemesis, uses high pressures and temperatures to convert carbon
to diamond. The diamonds produced from this method are slightly contaminated by the metal solvents they are grown in, and can be detected using infrared spectroscopy
. However, apart from this they are identical to natural diamonds, can be grown in large sizes (3 carat
and up), and are cheap to manufacture. Upon visual examination of such a stone, diamond experts have declared them to be rare yellow diamonds and priced them at $10,000-$15,000 before they were informed they were created in a lab.
The yellow color comes from the manufacturing process, but can be removed by longer processing.
Gemesis creates their diamonds in this way:
First, metal solvents and graphite are placed in a ceramic
growth chamber. A diamond seed is inserted as well. The chamber is placed in a compression sphere. Oil is forced into the top layer of the sphere, pushing up against steel anvils. The anvils increase the pressure. Electric current
is run through the chamber to create heat, up to 2,300 degrees Fahrenheit
. The graphite in the chamber atomizes, and the free carbon is drawn to a cooler end of the chamber, where it freezes onto the diamond seed. After three days, the ceramic chamber is removed and smashed
to reveal the diamond, which can then be cut and polished.
The second method, pioneered by Apollo Diamond, Inc. of Boston
, uses a carbon plasma
to grow their diamonds via chemical vapor deposition
(CVD). These diamonds are virtually flawless, and so far indistinguishable by any method from mined diamonds. Diamond experts believe they might be able to exploit
their perfectness, however, as these diamonds actually have fewer flaws than any natural stone. Apollo Diamond's stones can be colored or uncolored as well.
Apollo Diamond creates their diamonds in this way:
Diamond wafers are put in a chamber on a pedestral. The pressure is reduced to one tenth of an atmosphere. Hydrogen
gases are injected into the chamber and heated with a microwave
beam. At high temperatures (1,800 degrees Fahrenheit) a plasma forms when the electrons
leave their atomic nuclei
. The plasma "rains" onto the diamond wafer, depositing carbon. Minibricks of diamond are formed at the rate of half a millimeter
a day. These bricks can be cut into gemstones, or used in making semiconductors
. These wafers are one inch square, and are expected to reach four inches in five years. The price to manufacture one carat of CVD diamond is $5.
Beyond producing quality gemstones for much lower prices than mined ones, these diamonds are very exciting for their use as semiconductors. Currently, the heat produced by processors limit their speed, as high temperatures melt chips. However, diamonds are amazing conductors of heat, almost ten times better than alumuminum
. Researches at Apollo have been able to produce postive and negatively biased (p- and n-type) diamond layers by doping with boron
, the first step in making useful semiconductors.
De Beers has taken action against these synthetic diamonds, recognizing them as a serious threat to their stranglehold
on the diamond industry. Right now De Beers produces about half the natural diamonds in the world, and controls about two thirds of the diamond trade. Through successful advertising
("A Diamond is Forever") and tight restriction of the supply, they've vastly inflated
the prices for the gems. A cheap, ready source of diamond is anathema
to their empire.
They have fought back by instituting the Gem Defensive Programme, where they distribute, free of charge, the instruments
that can differentiate between some man made diamonds (using older processes) and their natural counterpart. The DiamondSure and DiamondView instruments are given to various gemstone labs to help keep artificial diamonds from interefering with sales
. But the new methods, especially chemical vapor deposition, produce stones identical to those found in mines. Currently all artificial diamonds sold in the US have to be called "synthetic", allowing purchasers a choice. Time will tell where the heart
of the consumer lies.