The recent article on synthetic diamonds in Wired magazine (September issue) has garnered a great deal of attention by the major print media and television networks over the past several weeks.

Gem synthetic diamond is an intriguing product, and the finished goods are certainly attractive materials. They should be. They have all the same optical, physical and chemical properties of natural diamond. Visually – even to the most experienced gemologists – they are indistinguishable from natural diamond.

Fortunately, we at GIA have stayed well ahead of the technology curve on synthetic diamonds for seven decades. Our first encounter came in the 1930s, when a scientist claimed he had created synthetic diamond. Through good science and hard work, GIA founder Robert M. Shipley and his son Robert Jr. proved the claim to be false.

In 1955, General Electric Co. scientists created the first-ever synthetic (industrial quality) diamonds, which we later characterized. And when GE announced the first cuttable gem-quality synthetic diamonds in 1970, we quickly provided identification criteria. Then, in the 1980s, when Sumitomo Corp. started selling gem synthetic diamond crystals for use as "heat sinks" in electronic equipment, we broke the news to the world with an in-depth 1986 article that clearly characterized the material and provided for conclusive identification of it. The following year, we worked intensely with De Beers’ research staff and reported on their synthetic diamonds, all produced for experimental purposes. Since then, we have reported regularly on synthetic diamonds in Gems & Gemology, including a comprehensive wall chart for the separation of natural from synthetic diamonds in 1995 and a landmark 1996 article by De Beers researchers on their detection instrumentation. To this day, we continue to keep the trade and the public informed—and confident—about our ability to detect gem synthetic diamonds, with an article in the Winter 2002 G&G (months before the Wired article) characterizing the new Gemesis synthetic diamonds and an August Insider report on the new single-crystal diamonds grown by chemical vapor deposition.

I hope that the media reports on synthetic diamonds mention the fact that the major laboratories can conclusively identify gem synthetic diamonds, that most of the material produced is still small and yellow in color, and that the sum of all commercially produced gem synthetic diamonds is but a minute portion of the entire worldwide diamond market.

For years, we have stated that there is nothing inherently wrong with synthetic diamonds. They are attractive and will no doubt find a market niche if they can be produced in sufficient quantities to warrant the huge investment necessary to create and sustain demand at appealing price points. Our view has remained consistent: The key is proper identification and distinction from natural diamond, as well as full disclosure in the marketplace. While the barrier to commercially produced gem synthetic diamond has been broken, our ability to identify the product has not. It is critical that we keep it so.

Gemesis Laboratory-Created Diamonds
Winter, 2002, Gems & Gemology
James E. Shigley, Reza Abbaschian, and Carter Clarke

High pressure is normally essential for the formation of gem-quality diamonds, whether in the Earth’s interior or in the laboratory. However, growth of synthetic diamond by chemical vapor deposition (CVD) techniques, which do not require high pressure, is drawing increased attention worldwide. The possible use of this technique to coat gemstones with polycrystalline CVD synthetic diamond was discussed by E. Fritsch et al. ("A preliminary gemological study of synthetic diamond thin films," Summer 1989 Gems & Gemology, pp. 84–90), but until recently, the technique has not seen much use in the gem industry due to the difficulty of growing single crystals that are large enough to be faceted. This may now be changing.

Using a patented CVD process (U.S. patent no. 6,582,513), Apollo Diamond Inc. of Boston, Mass., has successfully grown facetable laboratory-created diamonds. Four crystals (0.34-0.87 ct.) and four faceted samples (0.14-0.31 ct.) were submitted to the GIA Gem Laboratory for examination. The faceted samples ranged from faint brown to dark brown (see figure). Clarity was equivalent to VS₁ to SI₂; some small and irregularly shaped gray-black inclusions were observed in some samples, due to deposition of diamond-like carbon or graphite (as suggested by Raman spectroscopy). Characteristic strain patterns were observed, which were different from those seen in natural diamonds. Also, since no flux is employed in the growth process, the metallic inclusions typically seen in synthetic diamonds grown by HPHT processes are not present in CVD laboratory-grown diamonds. All of the samples fluoresced a very weak yellow-orange to long-wave UV radiation, and a weak to moderate yellow-orange to short-wave UV. As a characteristic feature, the CVD synthetic diamonds displayed strong red fluorescence while exposed to high-energy UV radiation in the De Beers DiamondView.

Infrared absorption spectra showed that the CVD laboratory-created diamonds were type IIa, and some contained trace amounts of isolated nitrogen. Photoluminescence spectra suggested the presence of N-V centers, indicated by very strong emission peaks at 575 nm and 637 nm. Also observed were features such as H-related absorption at 3123 cm^-1 in the mid-infrared range and a relatively strong photoluminescence emission at 737 nm due to trace impurities of silicon.

According to Apollo, gem-quality crystals weighing up to 3 carats could become available in the near future. Apollo is cooperating closely with the GIA Gem Laboratory to ensure that these CVD laboratory-grown diamonds are correctly identified before being introduced into the market. Gemological and spectroscopic studies of additional samples will be reported in a future article.