The inaugural event followed the December 2012 opening of the GIA gem grading laboratory in Tokyo. GIA regularly holds GemFests around the world, providing the latest gemological information to the public and diamond trade.
Speaking to members of the Japanese jewelry industry and GIA alumni, King noted that Japan is one of the world’s largest consumer markets for colored diamonds. “While colored diamonds have been coveted for centuries, it wasn’t until the mid-1990s that they really emerged on the mainstream jewelry market. These rare stones were once reserved for royalty and the very wealthy, but today are more and more prevalent in the broader gem market,” he added.
King discussed rare colors seen in the GIA lab, such as purple, pinkish-orange, green and blue-green, along with unusually large treated colors, High Pressure, High Temperature (HPHT) treated colors, synthetics and treated synthetics. He also reviewed the new trend of pale colored diamonds, which are equivalent to F, G, H and I on the D to Z scale.
The GemFest was opened by Mari Okada, executive manager of the GIA gem laboratory in Tokyo. “It is very important for GIA to be present in as such an important market as Japan not only with gem grading services, but also with latest information from GIA’s nine laboratories and international research effort,” she said.
Over the course of its 82-year history, GIA has evaluated many of the world’s most famous and significant colored diamonds, including the Hope, Dresden Green, Sun Drop and Wittelsbach-Graff.
Among the historically notable GIA-graded colored diamonds highlighted at the GemFest were the Princie Diamond, the De Beers Diamond, and the Bulgari Blue.
The Princie Diamond belonged to the Nizam of Hyderabad in the 18th century. The diamond is thought to have come from the famous Golconda mines in India, as it displays a rare orange-red fluorescence associated with Golconda-type diamonds. At 34.65 carats, it is one of the largest Fancy Intense pink diamonds ever seen by the GIA.
Meanwhile, the De Beers Diamond was discovered at a De Beers mine in 1888. The 208.65-carat Fancy Vivid Yellow diamond, VS2, was cut from 439.86 metric carats. It was displayed at the 1890 Exposition Universelle (World Fair) in Paris, and when put up for auction in 1982, was described as the world's fifth-largest cut diamond, though a number of larger diamonds graded by GIA have appeared in the market since.
The Bulgari Blue was purchased from the Bulgari store in Rome in 1972. The 10.95-carat blue diamond is paired in a ring containing a G VS1 9.87 carat colorless diamond.
King also highlighted significant colored diamonds evaluated by GIA that have been featured in recent auctions, including the Graff Pink, a 24.78 Fancy Intense Pink diamond that sold for $45.6 million at Sotheby’s Geneva in November 2010.
Other notable auction items included the record-breaking five-carat Fancy Vivid Pink sold for $2.1 million per carat; the 6.01 carat Fancy Vivid Blue sold for $10.1 million; the Sun Drop, a 110.03-carat Fancy Vivid Yellow diamond sold for $10.9 million; and the 4.19-carat Fancy Vivid Orange bought for $2.9 million.
The number of colored diamonds evaluated by the GIA laboratories has grown by around 30 percent since 2010. Yellow diamonds have remained the most common color, followed by pink.
A leading authority in the characterization and color description of colored diamonds, King began his career at GIA in 1978. He has been involved in the grading of many of the world’s important diamonds, including the Hope Diamond, the pink Agra, the yellow Tiffany, the Incomparable, the Centenary, and those in the Smithsonian’s Splendor of Diamonds exhibition.
With 25 years of laboratory experience, he has written a number of articles for GIA’s award-winning quarterly journal, Gems & Gemology, most notably, “Color Grading of Colored Diamonds in the GIA Gem Trade Laboratory.”
GIA opened its Tokyo laboratory in late 2012. The facility is GIA’s ninth global laboratory and the seventh outside of the United States. GIA has offered educational programs in Japan since the 1970s.