diamonds were weakly colored pink diamonds that had been coated to enhance their color. Since these diamonds were already pink, the gemological evidence necessary to prove treatment was very limited. The only foolproof method available to the standard gemologist was— and still is—to use magnification, especially a microscope. On a clean, uncoated diamond surface, only polish lines should be visible under a microscope; anything else must be suspect. For example, a coated surface will often appear iridescent when light reflects off of it. Again, proof of natural origin must take place at the laboratory level, but the microscope method can help separate natural diamonds from those that may not be. Synthetics Two types of synthetic pink diamonds are currently on the market, as both HPHT-grown synthetics and CVD grown synthetics can be treated to create pink colors. Similar to multi-step treated diamonds HPHT-grown pink synthetic diamonds start out as yellow and undergo artificial irradiation to get their pink color. These man-made diamonds are grown in a different environment than their natural counterparts, and this growth is a key to their detection. The growth appears often in an hourglass shape when visible within a synthetic diamond. This type of growth pattern is extremely uncommon in a natural color diamond. Often, too, a pink diamond that does not have the classic color bands but instead has color visible in wedges should be highly suspect. This growth is also commonly visible under UV light, specifically short wave. Also, since most synthetic pink diamonds undergo a similar treatment to treated color pink diamonds the orange fluorescence is similar. Another detection method is to view the inclusions (if any) within a diamond. The most common inclusions are metallic, which have very high relief (brightness). Also common are tiny pinpoint-like inclusions (also metallic) that are unusually arrayed within a synthetic diamond. Unlike natural diamonds, these inclusions appear evenly dispersed within a stone, while in natural diamonds they are either part of clouds or by themselves in no coherent pattern.
The future of pink diamonds Pink diamonds are unusual among natural color diamonds for several reasons, as noted above. But they are even more unusual because their source traces to just a single mine, which is expected to be played out in the next 10 years. Also as noted above, many investors are snapping up natural color pink diamonds in the expectation of significant price increases as supply dwindles. It is not the role of the NCDIA to get involved in value or pricing, but the long-term prospects for pink diamond supply are clear. Unless another diamond mine starts producing pink diamonds with some degree of regularity, these diamonds will only become more rare in the future. The ease with which people can learn about these extraordinary gems has made it that much more important for all of us in the industry to educate ourselves. Presenting yourself as an expert on these diamonds will only be effective if you are, in fact, an expert. NCDIA provides this newsletter, seminars, the NCDIA website, and all of our collateral information to help NCDIA members attain the necessary level of expertise to grow their businesses.
CVD-grown synthetics undergo similar processes to create their pink coloration. It Is currently believed that all pink CVD-grown synthetics are irradiated and annealed in a similar fashion to both natural diamond treated pink diamonds and HPHT synthetic pink diamonds. As before, orange fluorescence is quite common in these stones, and anything with this UV reaction should be considered quite suspect. Other features that may stand out are the even coloration of these synthetics. Most natural pink diamond display quite obvious color bands, especially type I diamonds. As with seemingly all color diamonds nowadays, confirmation from a laboratory is vital.
Images courtesy of Gemcut, S.A.
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