The unique set of conditions in nature that produce the structural imperfections (defects in the lattice of carbon atoms see Shigley and Breeding, 2013) responsible for the most vibrant hues of green, blue, and pink/red diamonds are so uncommon that many people are not even aware these stones exist. Interestingly, the rarest of diamond colors correlate with the three most popular choices for favorite color, in general-green, blue, and pink to red.
INTRODUCTIONįancy-color diamonds are among the most highly valued of gemstones due to their beauty and rarity.
By leveraging GIA’s vast database of diamond information, we have compiled data representative of tens of thousands of samples to offer a look at natural green diamonds that has never before been possible. Careful microscopic observation, gemological testing, and spectroscopy performed at GIA over the last decade allows an unprecedented characterization of these beautiful natural stones. Four different coloring mechanisms-absorption by GR1 defects due to radiation damage, green luminescence from H3 defects, and absorptions caused by hydrogen- and nickel-related defects-can be identified in green diamonds. Compounding that problem is a distinct paucity of published information on these diamonds due to their rarity. Laboratory irradiation treatments have been used commercially since the late 1940s to create green color in diamond and closely mimic the effects of natural radiation exposure, causing tremendous difficulty in gemological identification. Most of the world’s current production of fine natural green diamonds comes from South America or Africa. These diamonds are colored either by simple structural defects produced by radiation exposure or by more complex defects involving nitrogen, hydrogen, or nickel impurities. ABSTRACTĪmong fancy-color diamonds, natural-color green stones with saturated hues are some of the rarest and most sought after.
Natural-color green diamonds such as these rough (0.85–1.07 ct) and faceted (0.68–1.66 ct) stones submitted to GIA by clients or for scientific study are extremely rare and generally found in South America or Africa. Comprehensive CAD/CAM For Jewelry Certificateįigure 1.
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