Kadet, a 1994 National Jeweler Retailer Hall of Fame inductee, helped grow the family-owned retailer in the Chicago area and beyond.
‘Oppenheimer Blue’ Diamond Could Sell For $45 Million
The rectangular-cut, 14.62-carat stone will be the largest and finest fancy vivid blue diamond ever offered at auction when it goes up for sale at Christie’s Geneva next month.

Geneva--When Christie’s holds its Magnificent Jewels sale in Geneva next month, it will offer the largest and finest fancy vivid blue diamond ever seen at auction.
The “Oppenheimer Blue,” a rectangular-cut, 14.62-carat stone, is expected to sell for between $38 million and $45 million when it hits the auction block in May.
This big blue diamond was owned by a man who certainly knew a thing or two about the stones.
Sir Philip Oppenheimer controlled the Diamond Syndicate in London and began working in the family business at De Beers London in 1934, where he sorted and valued diamonds.
Later, as head of the London-based Central Selling Organisation for more than 45 years and chairman of the Diamond Trading Company branch, he oversaw a diamond sales business set up by De Beers to control the global diamond supply.
Christie’s Magnificent Jewels sale is scheduled to take place at the Four Season Hotel des Bergues on May 18.
The sale also will include a collection of 46 pieces that once belonged to H.S.H Gabriela Princess zu Leiningen, estimated to realize more than $15 million total and featuring pieces from brands such as Cartier, Boucheron, Tiffany & Co. and Van Cleef & Arpels.
The Princess comes from a successful German entrepreneurial and philanthropic family. She was married to Prince Karl-Emich zu Leiningen for seven years and also was a qualified lawyer who became a consultant for UNESCO, advising on equality and women’s rights.
In May 1998, Princess Gabriela married His Highness Prince Karim Aga Khan IV, 49th Imam of the Ismaili community and international entrepreneur. During their 16-year marriage, the Princess held the title Begum Inaara Aga Khan and received a number of jewels from her-then husband to build upon her already large collection.
Click through she slideshow below to see six of the pieces belonging to the princess that will be up for auction.
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