Deepdene (diamond)

For other uses, see Deepdene (disambiguation).

Deepdene

Weight	104.52 carats (20.904 g)
Color	VVS1
Cut	Cushion cut
Mine of origin	Premier Mine
Cut by	Harry Winston
Original owner	Cary W. Bok

The Deepdene is a 104.52 carats (20.90 g) yellow diamond widely considered^{[by whom?]} to be the largest irradiated diamond in the world.

Origin of the name

The Deepdene gets its name from the Pennsylvania estate of Mrs. Bok, wife of Cary W. Bok, both the diamond's original owners. At the time, the Deepdene weighed slightly more at 104.88 carats (20.98 g) and was mounted in a diamond clip. Harry Winston bought the diamond from the Boks in 1954 and it eventually found its way to a London firm in 1960 and later to a German owner.

Irradiation scandal

On 27 May 1971, Christie's auction house in Geneva offered to prospective buyers the cushion-cut, fancy golden-yellow diamond which would only later come to be known as the "Deepdene." Its clarity was stated as VVS1 (with two very small imperfections near the girdle or midsection of the stone) and its vivid-yellow colour was guaranteed to be natural by both the German gemological institute and the University of Mainz.^{[citation needed]}

However, Dr. Eduard Gübelin, the founder of Gübelin Gem Lab in Lucerne, Switzerland, had the opportunity to inspect the diamond before the auction took place. Gübelin's experience with examining gemstones and recognizing artificially colored diamonds led him to declare that the Deepdene had been irradiated, likely by neutron bombardment.^{[citation needed]} Gübelin warned Christie's and any buyers who would listen, but the sale was allowed to continue with the recommendation that the stone be examined by another lab.^{[citation needed]}

After being sold to jewelers Van Cleef & Arpels for a reported £190,000 (about US$460,000 at the time), the Deepdene was sent to the Gem Testing Laboratory in London, England.^{[citation needed]} The lab's director, gemological pioneer Basil Anderson, was given the task of substantiating Gübelin's claims.^{[citation needed]} That he did, using spectral analysis, with damning results. Van Cleef & Arpels promptly returned the stone for a refund, leaving it somewhat of an unwanted orphan. Its current whereabouts remain uncertain.^{[citation needed]}

Assuming Winston did not have the irradiation treatment done, it could have taken place any time between 1955 (when Winston sold it) and 1971, the year it was offered at auction.^{[citation needed]} The recutting of the gem from 104.88 carats (20.98 g) to 104.52 carats (20.90 g) was most likely intended to remove the 'umbrella' coloration pattern it had around its culet. This was a common side effect seen in early irradiated diamonds but irradiation technique has been improved upon so that it no longer occurs.^{[citation needed]}

References

• Balfour, Ian (February 2001). Famous Diamonds (4th Hardback ed.). Suffolk, England: Antique Collectors' Club. p. 302. ISBN 0-903-43265-X.