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Colored Diamonds Shine at GIA’s GemFest in Tokyo

Lab’s Chief Provides an Update

Apr 14, 2013 7:47 AM   By GIA
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Press Release: Members of the Japanese gem and jewelry industry gained exclusive insights into the world of colored diamonds when John King, the Gemological Institute of America's (GIA) chief quality officer and noted expert on colored diamonds, presented an update at the Institute’s GemFest in Tokyo on April 11. This 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 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, HPHT (high pressure, high temperature) 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.

Mari Okada, executive manager of the GIA gem laboratory in Tokyo, opens GIA’s inaugural GemFest in Tokyo.

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 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, this one of the largest Fancy Intense pink diamonds ever seen by GIA.

The De Beers Diamond was discovered at the DeBeers 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 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.

The 41 carat Dresden Green diamond, one of the few green diamonds that is known to be of natural color, in a hat ornament made by Prague jeweler Diessbach in 1768. The flowery bottom portion was originally fashioned by Geneva jeweler Andre Jacques Pallard in 1746 as a section of a badge of the Order of the Golden Fleece. Image © GIA.

The historic Wittelsbach Blue diamond was sold for a record-breaking $24.3 million to London jeweler Laurence Graff at Christie's in December 2008. It was subsequently recut to 31.06 carats, as shown above, and renamed the Wittelsbach-Graff.

King also highlighted significant colored diamonds evaluated by GIA that have been featured in recent auctions, including the Graff Pink, a 24.78 carat, 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 5 carat fancy vivid pink ($2.1 million per carat); the 6.01 carat fancy vivid blue ($10.1 million); The Sun Drop, a 110.03 carat fancy vivid yellow ($10.9 million); and the 4.19 carat fancy vivid orange ($2.9 million).

The number of colored diamonds evaluated by the GIA laboratories has grown steadily at around 30 percent since 2010. Yellow diamonds have steadily 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. For more details, visit

About GIA
An independent nonprofit organization, GIA (Gemological Institute of America), established in 1931, is recognized as the world’s foremost authority in gemology. GIA invented the famous 4Cs of Color, Cut, Clarity and Carat Weight in the early 1950s and in 1953, created the International Diamond Grading System™ which, today, is recognized by virtually every professional jeweler in the world.

Through research, education, gemological laboratory services, and instrument development, the Institute is dedicated to ensuring the public trust in gems and jewelry by upholding the highest standards of integrity, academics, science, and professionalism. Visit

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