Origin of name
The original owners of the "Deepdene Diamond," Mr. & Mrs. Cary W. Bok of Pennsylvania State, U.S.A. owned an estate in Pennsylvania known as the Deepdene Estate, from which the diamond derives its name.
Characteristics of the diamond
The Deepdene diamond is a 104.52 carat, fancy vivid yellow, cushion-cut diamond with a clarity grade of VVS-1 (very very slightly included).
Being identified as an artificially irradiated diamond, the Deepdene that was discovered in the Premier Mines of Transvaal, South Africa, probably would have been initially a Type Ia diamond, with a pale to medium yellow color, and the nitrogen atoms associated as groups. However, when the diamond was subjected to radiation treatment probably by neutron bombardment, some of the groups of nitrogen atoms were scattered as single atoms, which imparted the intense yellow color to the diamond, thus converting it to a Type Ib diamond. Thus the Deepdene is a nitrogen-containing color enhanced diamond.
Some irridiated natural diamonds
History
The Deepdene diamond has acquired the infamous title of being the largest irradiated diamond in the world, and has achieved the status of an "outcast" in the world of famous diamonds, to the extent that even it's current whereabouts remain uncertain.
Nevertheless, the story of the Deepdene is so fascinating, that it is still worthwhile repeating it, for the sake of all lovers of diamonds and connoisseurs around the world.
The Deepdene was a diamond mined in the Premier Mines of Transvaal, South Africa, belonging to De Beers Consolidated Mines Ltd. Mr. & Mrs. Cary W. Bok of Pennsylvania State, U.S.A. who owned the diamond, named it after their estate in Pennsylvania known as the Deepdene Estate. The original weight of the Deepdene was 104.88 carats and the stone was mounted on a diamond clip.
The Boks disposed of the Deepdene in 1954, and was purchased by Mr. Harry Winston. The diamond eventually found it's way to a firm in London in 1960, and was finally acquired by it's German owner.
The German owner of the diamond put up the Deepdene for sale on May 27th, 1971, at a Christie's auction, held in Geneva. Christie's auction house advertised the gem as a 104.52 carat, fancy golden-yellow diamond. The Clarity of the stone was given as VVS-1, which is only slightly less than the internally flawless clarity grade. The VVS-1 grading was probably due to two very small imperfections near the girdle of the stone. The color grading of the diamond was fancy vivid yellow, which is the highest grading for any color. The super grade color of the diamond was guaranteed natural by both the Gemological Institute of Germany and the University of Mainz, in Germany.
However, Dr. Edward Gubelin, a renowned scientist and gemologist from Geneva, who had a keen eye and a wealth of experience in examining gems, and was quite adept at recognizing artificially colored diamonds, had the opportunity to inspect the diamond before the auction took place. To his utter dismay, Dr. Edward Gubelin, discovered that the Deepdene had been irradiated, most probably by neutron bombardment. Dr Gubelin immediately warned Christie's and any buyer who was prepared to listen to him, about the dubious nature of the stone, but Christie's allowed the sale to continue, with the recommendation that the prospective buyer examines the diamond at a different laboratory.
The jewelers Van Cleef & Arpels purchased the diamond for a sum of £190,000 at the auction. The company decided to send the Deepdene to a renowned gem testing laboratory in London, in the United Kingdom. The director of the lab, a pioneer gemologist, Basil Anderson, was assigned the task of verifying the credentials of the Deepdene. Dr. Anderson subjected the diamond to spectral analysis, and the results confirmed the initial findings of Dr. Edward Gubelin.
Van Cleef & Arpels lost no time in returning the irradiated diamond for a refund, and so ends the story of the Deepdene, which became an unwanted orphan in the world of famous diamonds. But, at what point the diamond was irradiated after it left the custody of the Bok's, remains a mystery to this day. The present whereabouts of the Deepdene is unknown.
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