Artificial diamonds are real diamonds, created in laboratories, with the same chemical, physical and optical properties. They have extreme hardness, broad transparency, high thermal conductivity and high electrical resistivity. For the moment only colored artificial diamonds are present on the market. The color is given by nitrogen impurities, like in natural ones.
There are two common procedures of obtaining an artificial diamond:
- High-Temperature High-Pressure (HTHP) and Chemical Vapor Deposition (CVD).
HTHP converts carbon to diamond usually by using a tiny piece of natural diamond bathed in a solution of graphite and a catalyst at approximately 1,500 °C and 58,000 atm of pressure. Carbon will precipitate onto the diamond seed crystal.
- CVD produces diamond coatings by heating a hydrocarbon gas over a metal surface.
The first synthetic diamond was obtained in December, 1954 by Dr. Tracy Hall from General Electric and was officially announced in 1955.
Nevertheless, in the book „The New Alchemists: Breaking Through the Barriers of High Pressure”, by Robert M. Hazen it appears that the first ones to discover the technology for obtaining artificial diamonds were in fact the Swedish, even if the fact was never officially announced. This happened in 1953 but their technology permitted obtaining only fraction-carat gems and was never further developed as a consequence of the announcement of General Electric.
In mid-1960s the Russians made an official statement announcing they had developed a technology of producing diamonds. The procedure was similar to that used by General Electrics but it was based on Russian research in high-pressure physics.
In 1970 the costs of producing synthetic diamonds were still exceeding the costs involved in finding real diamonds. Now, synthetic diamonds are present on the market with significantly lower prices than the price of natural fancy yellow diamonds.
Properties of Artificial Diamonds
- only fancy yellows have been present on the market so far, due to nitrogen introduced during processing. Colorless diamonds have also been produced, but not for commercial use yet. Specialists are working on this problem and we can expect to see at least color grades in the near future.
- size has also evolved from diamonds of less than 1ct. in the rough to full-carat and larger stones.
- clarity can reach the VS1 grade.
Tests to Determine The Nature of Diamonds
To detect whether diamonds are natural or synthetic, several tests are performed in specialized diamond-grading laboratories:
- the refractory qualities are analyzed by shining a light through the diamond.
- the crystal structure is revealed by using ultraviolet light.
- synthetic diamonds have a red-colored fluorescence when exposed to high-energy ultraviolet radiation in the De Beers DiamondView (a specialized equipment for diamond analysis).
- Diamond Trading Company Research Centre has demonstrated that CVD single-crystal diamond shows a range of different impurity related features not seen in a natural diamond. GIA has a more detailed article about this.
The only way to make a conclusive judgment of a diamond's origin is to consider as many aspects of its analysis as possible.
As artificial diamonds constitute a source of potential fraud, they should be properly labeled so that the purpose of their creation be reached: offering consumers more affordable alternatives.
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