Oppenheimer Blue Diamond
ORIGIN OF NAME
The "Oppenheimer Blue Diamond" gets its name from its previous owner, Sir Philip Oppenheimer, a member of the Oppenheimer family that controlled the De Beers Mining Company and its subsidiary Diamond Trading Company from 1929 to 2012 . He was a cousin to Harry Oppenheimer, who succeeded as Chairman of the Company after his father Earnest Oppenheimer's death in 1957. Sir Philip was the head of the London-based Central Selling Organization from 1948 until the end of 1993, in which capacity he steered the activities of the diamond cartel set up by De Beers and successfully controlled the sale of nearly all diamonds produced by the mines of the company in South Africa, as well as other mines belonging to the cartel elsewhere, including the Soviet Union.
Sir Philip began working in the family business in London in 1934, sitting at a bench sorting and valuing diamonds. He served in the British army as a lieutenant colonel during World War II, participating in the invasion of Sicily. After the war he returned to his family business at De Beers London, and succeeded as the head of the sales cartel in 1948 afterr the death of his father Otto Oppenheimer.
Sir Philip was well known in Britain for his involvement in horse racing. In addition to owning a stable of winning horses, he pushed De Beers into sponsoring the King George VI and Queen Elizabeth Diamond Stakes at Ascot, one of the nation's most prestigious races, each July.
His involvement with diamonds since 1934, made Sir Philip not only a key figure in the international diamond trade, but also a connoisseur of diamonds himself, that led to selection of some of the best diamonds that passed through his hands for his personal collection. One such extraordinary diamond, is a blue diamond rough recovered at the Premier Diamond Mines, belonging to De Beers, which Sir Philip got the Company's master cutters to fashion into a cut-cornered rectangular emerald-cut diamond, which was subsequently mounted on a Verdura "Eight Blades" mounting by the New York based Amercan fine jeweler Verdura.
CHARACTERISTICS OF THE DIAMOND
The 4Cs of the Diamond
At the time the Oppenheimer blue diamond was first mounted on a Verdura "Eight Blades" mounting, its weight was actually 14.71 carats. After the death of Sir Philip Oppenheimer on October 8, 1995, the Oppenheimer Blue diamond on its original Verdura "Eight Blades" mounting was apparently sold to an anonymous buyer in 1999, who got the diamond dismounted from this setting, and after getting it slightly re-cut and repolished, got it set as the centerpiece of the present size 6, platinum ring, flanked on either side by a trapeze-cut diamond. The new weight of the Oppenheimer blue diamond was 14.62 carats.
The Oppenheimer Blue Diamond as it is today, is a 14.62-carat, cut-cornered rectangular emerald-cut, VVS-1 Clarity, fancy-vivid blue diamond, with excellent polish and symmetry.
Reasons that may have led the Master Cutters of the Oppenheimer Blue Diamond to Employ the Rectangular Emerald-Cut ?
When selecting a cut for blue diamond roughs due consideration is given to their extreme rarity and restricted sizes, that necessitates the application of the not so desirable maxim for cutting diamonds in general, viz. maximizing for quantity at the expense of quality. Round brilliant-cuts are not a popular choice for extremely rare colored diamonds mainly due to this reason, as the wastage involved in employing such cuts is usually more than 50%.
The somewhat elongated shape of the gem-quality area of the Oppenheimer blue diamond rough would have also contributed to the decision to employ the rectanguar emerald-cut. The reasonable clarity (VVS-1 Clarity) of the diamond rough might also have had a bearing on this decision, as the emerald-cut with its broad, open facets will make any inclusions in the diamond very obvious. This also applies to the color-saturation and color-distrbution inside the diamond. Hence, the emerald-cut is only employed on diamonds with a superior clarity, color saturation and color distribution. The Oppenheimer blue diamond rough undoubtedly satisfied all these requirements. Hence, the decision to cut the Oppenheimer blue diamond as a cut-cornered rectangular emerald-cut diamond.
Having employed the emerald-cut on the Oppenheimer blue diamond, the decision to mount it as the centerpiece of a platinum ring with accent diamonds was the most appropriate. This is because accent stones fit next to the emerald cut diamond more neatly and easily than they would next to diamonds of any other cut. The captivating image of the Oppenheimer blue diamond platinum ring with its trapeze-cut colorless diamond accents, provided ample proof for this contention.
The Saturated Fancy Vivid Blue Color of the Oppenheimer Blue Diamond
The fancy vivid blue color of the Oppenheimer Blue Diamond is the highest color grading that can be given to colored diamonds. Many blue diamonds are modified with a slight grey hue, or have an uneven saturation with colorless areas interspersed. However, the Oppenheimer Blue Diamond is endowed with a splendid, even and saturated pure blue hue, that makes it a natural wonder to behold !!!
Position of the Oppenheimer Blue Diamond in the List of known famous blue diamonds arranged in descending order of carat weights
In the list of known famous blue diamonds arranged in descending order of carat weights, the 14.62-carat Oppenheimer Blue Diamond occupies the 17th position. See table below.
|
S/N |
Name |
Price realized at Auction/Value when last sold | Country/Period of Origin |
Carat weight |
Cut/Shape |
Color/Clarity |
| 1 | Unnamed cushion-cut blue diamond | Cut from a 704.56-carat rough diamond Valued between $45-50 mill. | 261.00 | Cushion-cut | fancy blue | |
| 2 | Unnamed brilliant | 51.84 | Round-brilliant | fancy blue | ||
| 3 | Copenhagen Blue diamond | Named in honor of an exhibition in Copenhagen in 1960 | Jagersfontein Mine, South Africaa | 45.85 | Emerald-cut | fancy blue |
| 4 | Hope diamond |
Over $300,000 in 1911. Current estimate $200-$250 mill. |
Golconda, India 1663-68 | 45.52 | Antique-cushion brilliant |
fancy dark grayish- blue/VS1 |
| 5 | Tereschenko | $4.6 mill. Christie's Genv. sale Nov.1984 | Golconda, India | 42.92 | Pear-shaped | fancy blue |
| 6 | Graff Imperial Blue | Guinea | 39.81 | Pear-shaped | fancy light blue/IF | |
| 7 | Crown of Charlemagne | Last sold by Harry Winston in 1967 | 37.05 | Old-European cut | fancy light blue | |
| 8 | Wittelsbach-Graff | $24.3 mill. | Gloconda, India | 35.56 /31.06 | Cushion-shaped | fancy deep blue/IF |
| 9 | Sultan of Morocco | $250,000 in 1972, Private sale | Golconda,India | 35.27 | Cushion-cut | fancy grayish blue |
| 10 | Cornflower Blue diamond-1 | Sold by Harry Winston in 1969, later re-purchased and sold to a Middle eastern client in 1971. | Premier Mine, S.A. | 31.93 | Pear-shaped | fancy blue |
| 11 | The Blue Heart or Eugenie Blue | $300,000 in 1953. Sale by Van Cleef & Arpels after change of setting | Premier Mine, S.A. | 30.82 | Heart-shaped | fancy vivid blue |
| 12 | Blue Lili | Premier Mine, S.A. | 30.06 | Tapered cushion-cut | fancy intense blue | |
| 13 | The Heart of Eternity | Premier Mine, S.A. | 27.64 | Heart-shaped | fancy vivid blue/VS2 | |
| 14 | Transvaal Blue | Premier Mine, S.A. | 25.00 | Pear-shaped | fancy blue | |
| 15 | Sam Abram Fancy Blue diamond | $9.9 mill. Soth.NY. Oct 1994 | Premier Mine, S.A. | 20.17 | Emerald-cut | fancy vivid blue/VS2 |
| 16 | Graff Blue Ice Diamond | Premier Mine, S.A. |
20.02
|
Pear-shaped | fancy deep blue | |
| 17 | Oppenheimer Blue Diamond | US$57.5 million, Christie's Geneva, May 2016 | Premier/Cullinan Mine |
14.62 |
Rectangular Emerald-cut | fancy vivid blue/VVS1 |
| 18 | The Blue Empress | Premier Mine, S.A. | 14.00 | Pear-shaped | fancy blue | |
| 19 | The Begum Blue | $7.75 mill. Christie's Geneva. November 1994 | Premier Mine, S.A. | 13.78 | Heart-shaped | fancy deep blue |
| 20 |
Brunswick Blue-1 Previously believed to have been cut from the French Blue diamond |
Part of the Duke of Brunswick collection of jewels sold in 1874 | Golconda, India | 13.75 | Pear-shaped | fancy blue |
| 21 | Cut-cornered rectangular mixed-cut blue diamond |
$8.87million Christie's Geneva, May 2008 |
Premier Mine, S.A. | 13.39 | Cut-cornered rectangular mixed-cut | fancy intense blue |
| 22 | Marquise-cut fancy blue diamond | $7.6 million Christie's Hong Kong, May 2011 | Premier Mine, S.A. |
13.39
|
Marquise-cut | fancy blue/VVS2 |
| 23 | Winston Blue Diamond | US$23.8 million, Christie's Geneva, May 2014 | Premier/Cullinan Mine, S.A. |
13.22 |
Pear-shaped | Fancy vivid blue/FL |
| 24 | Cornflower Blue diamond-2 | Set in a ring and sold by Harry Winston in 1969 | Premier Mine, S.A. |
12.39
|
Round brilliant | fancy blue |
| 25 | Blue Moon of Josephine Diamond | US$48.4 million, Sotheby's Geneva, Nov. 2015 | Premier/Cullinan Mine, S.A. |
12.03 |
Cushion-cut | fancy vivid blue/FL |
| 26 | The Blue Magic | Premier Mine, S.A. | 12.02 | Modified pear-shaped | fancy vivid blue/VVS2 | |
| 27 | Bulgari Blue | $15.7 mill. Christ.NY Oct.2010 | Premier Mine, S.A. | 10.95 | Triangular-shaped | fancy vivid blue |
| 28 | Sotheby's Geneva, Nov 2012 | $10.8 mill. |
10.48 |
Briolette | fancy deep blue | |
| 29 | Zoe Diamond | US$32.645 mill. Sotheby's New York, Nov. 2014 | Premier/Cullinan Mine, S.A. |
9.75 |
Pear-shaped | fancy vivid blue/VVS2 |
| 30 | Christie's N.Y. April 2007 | $2..4 million | 9.39 | Cushion-cut | fancy grayish blue | |
| 31 | Sotheby's HK. Oct. 2009 | $5.7 mill.Soth.HK. | Premier Mine, S.A. | 8.74 | Emerald-cut | fancy intense blue/VVS1 |
| 32 | Sotheby's HK. April 2012 | $12.7 mill. | 8.01 | Emerald-cut | fancy vivid blue | |
| 33 | Christie' Geneva, Dec.1999 | $3.2 million | Premier Mine, S.A. | 7.96 | Pear-shaped | fancy vivid blue/VS1 |
| 34 | Soth. Geneva May 2010 | $8.03 mill. | Premier Mine, S.A. | 7.64 | Cushion-cut | fancy intense blue/VVS2 |
| 35 | Premier Blue Diamond | Auction coming up on October 7, 2013 | Premier Mine, S.A. | 7.59 | Round brilliant-cut | fancy vivid blue |
| 36 | Christie's Hong Kong. April 2002 | $2.6 mill. | Premier Mine, S.A. | 7.15 | Pear-shaped | fancy vivid blue |
| 37 | Petra Blue/Star of Josephine | $9.5 mill. Soth. Geneva. May 2009 | Premier / Cullinan/Petra Mine.S.A. | 7.03 | Cushion-cut | fancy vivid blue/IF |
| 38 | Brunswick Blue-2 | Part of the Duke of Brunswick collection of jewels sold in 1874 | Premier Mine, S.A, | 6.50 | Pear-shaped | fancy blue |
| 39 | Christie's New York | $3.6 mill | Premier Mine, S.A. | 6.29 | Pear-shaped | fancy intense blue |
| 40 | Graff Blue diamond | Premier Mine, S.A. | 6.19 | Pear-shaped | fancy intense blue | |
| 41 | Moussaieff Jewelers unnamed blue diamond | $7.98 mill Sotheby's HK, Oct.2007 | Premier Mine, S.A. | 6.04 | Emerald-cut | fancy vivid blue |
| 42 | Sotheby's HK, Oct.2011 | $10.1 mill. Soth.HK. | Premier Mine, S.A. . | 6.01 | Emerald-cut | fancy vivid blue |
| 43 | Sotheby's Geneva, Nov.2009 | $7.5 mill | Premier Mine, S.A. . | 5.96 | Pear-shaped modified brilliant | fancy vivid blue |
| 44 | Christie's Geneva, Dec.1999 | $1.13 mill. | Premier Mine, S.A. | 5.80 | Pear-shaped | fancy intense blue/IF |
| 45 | Marie Antoinette Blue diamond | Set in a ring said to have belonged to Marie Antoinette. Last offered for sale in1983 but not sold |
Golconda,India |
5.46 | Heart-shaped | fancy grayish-blue |
| 46 | De Beers Millennium Blue, Jewel II- Apr.2010 Sotheby's HK | $6.4 mill. Soth.HK. |
Premier Mine, S.A. |
5.16 | Pear-shaped | fancy vivid blue/IF |
| 47 | toi et moi ring - Soth. Geneva May 2010 | $6.32 mill. | Premier Mine, S.A. |
5.02 5.42 |
Pear-shaped Pear-shaped |
fancy vivid blue D-color |
| 48 | Christie's Geneva, Dec.1999 | $1.24 mill. | Premier Mine, S.A. | 4.77 | Circular-cut | fancy deep blue/VS2 |
| 49 | Soth. Geneva. Nov,2007 | $4.7 mill | Premier Mine, S.A. | 4.16 | Pear-shaped | fancy vivid blue/ |
| 50 | Bulgari Blue | $2.97 mill. Bonhams Lond. 2011 | Premier Mine, S.A. | 3.78 | Pear-shaped | fancy vivid blue |
| 51 | Soth. Geneva May 2008 | $4.96 mill | Premier Mine, S.A. | 3.73 | Pear-shaped | fancy vivid blue |
| 52 | Aleks Paul of Essex Global Trading | $3.6 mill Christie's NY Apr. 2011 | Premier Mine, S.A. | 3.25 | Square Emerald cut | fancy vivid blue/IF |
| 53 | Christie's NY Oct.2011 | $2.7mill | Premier Mine, S.A. | 3.21 | Modified Pear-shape | fancy vivid blue |
| 54 | Sotheby's NY. Apr. 2011 | $3.27 mill | Premier Mine, S.A. | 3.18 | Marquise-cut | fancy vivid blue/IF |
| 55 | Sotheby's Geneva, Nov. 2009 | $2.5 mill. | Premier Mine, S.A. | 3.17 | Brilliant-cut | fancy intense blue /IF |
Please do not copy our tables. We may be compelled to inform the search engines if our content and tables are plagiarised and/or file a DMCA Request (Digital Millennium Copyright Act) .
The table also shows that the Oppenheimer Blue Diamond is actually the 3rd-largest emerald-cut blue diamond in the world, after the 45.85-carat, emerald-cut, Copenhagen blue diamond and the 20.17-carat, emerald-cut, fancy-vivid blue, Sam Abram blue diamond.
The 45.85-carat Copenhagen blue diamond is a fancy blue diamond and the 20.17-carat Sam Abram blue diamond is fancy vivid blue. Hence, the Oppenheimer Blue Diamond is the second largest emerald-cut fancy vivid blue diamond in the world.
According to Christie's, who put up the rare blue diamond for sale, at their Geneva Magnificent Jewels auction held on May 18, 2016, the Oppenheimer Blue Diamond is the largest Fancy Vivid blue diamond to ever appear at a Christie's auction. However,it must be noted that the largest, emerald-cut, fancy-vivid blue diamond to ever appear at an auction was the 20.17-carat Sam Abram blue diamond, which appeared at a Sotheby's New York auction in October 1994 and sold for US$ 9.9 million, after a bidding war between New Yorker Sam Abram, representing a Hong Kong concern and renowned Saudi jeweller and diamond dealer Sheik Ahmed Fitaihi. The price of US$ 9.9 million was then the highest price ever paid for a blue diamond at an auction.
The Oppenheimer Blue Diamond is an extremely rare Type IIb Diamond
Blue diamonds fall under the rare category of Type IIb diamonds, whose natural occurence is less than 0.1 % of all naturally occuring diamonds. The diamond is Type II because of the absence of detectable quantities of nitrogen. It is Type IIb, because of the presence of extremely minute quantities of Boron, which not only impart a blue color to the diamonds but also make the diamond semi-conducting. Hence the Oppenheimer Blue Diamond is a rare Type IIb diamond.
Type IIa diamonds on the other hand are chemically pure without any impurities and constitute about 1-2% of all naturally occuring diamonds. Type IIa diamonds can be either structurally perfect, structurally imperfect or naturally irradiated. Chemically pure and structurally perfect Type IIa diamonds (1-2%) are absolutely colorless and fall under the color-grade D, E & F. Chemically pure and structurally imperfect or plastically deformed diamonds (Less than 0.1%) acquire rare fancy colors such as pink, red, orange, violet, and brown. Chemically pure and naturally irradiated diamonds (Less than 0.1%) acquire a rare green color.
HISTORY
Early History of the Diamond
The mine of origin of the diamond
The early history of the diamond such as the country and mine of origin, the date of discovery, the weight of the rough diamond, etc. are not known. However, the diamond being a De Beers diamond, most probably originated from one of their mines in South Africa. Out of all the mines operated by De Beers in South Africa, the mine that was well known for its production of blue diamonds in the world, after the exhaustion and closure of the ancient source of blue diamonds in the world, viz. the Kollur mines of Golconda, in Southeastern India, is the Premier/Cullinan/Petra diamond mines. The Premier/Cullinan mine discovered in South Africa in 1902 by Sir Thomas Cullinan, in Transvaal, South Africa, eventually became one of the most productive diamond mines in the world. Some of the world's largest rough diamonds, such as the 3106-carat Cullinan rough diamond, the 755-carat Golden Jubilee rough diamond and the 599-carat Centenary rough diamond were discovered in these mines. The Premier mine is also the source of several high quality colored diamonds, including the very rare blue diamonds. The eleven exceptional quality blue diamonds that constituted the De Beers Company's limited edition Millennium Diamonds Collection, that was exhibited at the Millennium Dome, throughout the year 2000 were all sourced from the Premier diamond mines.
The approximate weight of the rough diamond that yielded the Oppenheimer Blue diamond
According to the website miningweekly.com the first transaction involving the Oppenheimer blue diamond took place around 1999, when the diamond weighed approximately 14.71 carats. It was subsequently recut slightly and repolished to its current weight of 14.62 carats. The website also gives an estimate of the weight of the Oppenheimer blue rough diamond, assuming that the rough gem yielded only one blue diamond, and also assuming a loss of weight of just over 50% in the cutting and polishing process. Accordingly, the rough stone was estimated to weigh between 30 to 35 carats.
Was the diamond purchased by Sir Philip Oppenheimer as a gift for his wife Pamela Fenn Stirling ?
The website miningweekly.com further states that the Oppenheimer Blue Diamond was purchased by Sir Philip Oppenheimer, and mounted on a platinum ring as a gift for his wife, Pamela Fenn Stirling, but unfortunately little is known as to when the diamond was purchased and how much was paid for it.
Christie's announces the sale of the Oppenheimer Blue Diamond at its Geneva Magnificent Jewels Sale coming up on May 18, 2016
In a Press Release dated 31st March, 2016, Christie's Auction House announced the sale of the "Oppenheimer Blue Diamond," the largest fancy vivid blue diamond ever offered at an auction, at its Geneva Magnificent Jewels Sale, coming up on May 18, 2016. In the press release the auction house further stated,
"Christie’s is proud to present the Oppenheimer Blue, the largest and finest Fancy Vivid Blue diamond ever offered at auction. Weighing 14.62 carats, this exceptional stone will lead Christie’s auction of Magnificent Jewels, held at the Four Seasons Hotel des Bergues. This exceptional blue diamond, named in honor of its previous owner Sir Philip Oppenheimer, is estimated at US$38-45 million.
"On May 18th, Christie’s will present the largest and finest Fancy Vivid Blue diamond ever seen. This stunning Fancy Vivid Blue rectangular-cut gem promises to create a media sensation as it travels around the world, fascinating both collectors and gem enthusiasts alike, before it makes its way to the auction block in Geneva."
Commenting on the auction of the rare blue diamond, Chairman of Christie's Asia Pacific and China, François Curiel said, "During my 47 years at Christie’s, I’ve been lucky enough to have handled and auctioned some of the world’s most legendary blue diamonds. The Oppenheimer Blue was named in honour of a very special connoisseur — its previous owner, Sir Philip Oppenheimer. The Oppenheimers have been leaders in the diamond industry for generations and Sir Philip could have had any diamond he wanted. But he chose this one, with its perfect hue, impeccable proportions and fabulous rectangular shape."
"Blue diamonds have gained a wider following, not only because they are stunning, but because there are so few of them available in the world. The Oppenheimer Blue can only be described as one of the rarest gems in the world. It is the gem of gems."
Oppenheimer Blue Diamond Sells in 25 minutes, a Record Time for a Record-Setting Amount for Any Jewel Sold at Auction
The Oppenheimer Blue diamond was assigned Lot No. 242 at the Christie's Geneva Magnificent Jewels Sale held on May 18, 2016 and given the title, "The Oppenheimer Blue, A Sensational Colored Diamond Ring," with a pre-sale estimate of CHF 38,000,000 - 45,000,000 (US$ 38,942,594 - 46,116,230) placed on it. GIA report No. 10387774 dated 14 May 2015, accompanying the lot, stated that the diamond is Fancy Vivid Blue, natural color, VVS1 clarity. A hardbound monograph also issued by the GIA featured additional photography, data collection charts and gemological research, attesting to the rarity and provenance of the Oppenheimer Blue Diamond.
There was an aura of excitement as the auction of Lot 242, led by Rahul Kadakia, Christie’s International head of jewelry, began. Bidding for the gem started at 30 million Swiss Francs below the lower estimate of 38 million. At the beginning bidding was quite slow, with long silent pauses, and incremental biddings of 200,000 Swiss Francs. Every time the bidding passed a million francs, there was a round of applause. Rahul Kadakia patiently accepted all bids, however small it was, and at one point commented, "its only once in a lifetime we have a stone like this."
As the bidding surpassed the lower estimate of CHF 38 million, the exceptional blue diamond inspired fierce bidding among collectors in three continents, finally reducing to a triangular contest between three private collectors, in the tense final moments. The auction room broke out into applause after 25 minutes of bidding, when the hammer was finally brought down in favour of an unidentified bidder at a whopping CHF 56,837,000 equivalent to US$ 57,541,779.
Oppenheimer Blue Diamond Sets the World Record for any Jewel Sold at an Auction
At a whopping US$ 57,541,779 the Oppenheimer Blue Diamond has set the world record for any jewel sold at an auction, which was previously held by the "Blue Moon of Josephine Diamond" that sold for US$ 48.4 million at Sotheby's Geneva Magnificent Jewels Sale held in November 2015. Other records set by the diamond are :-
1) The world's most expensive diamond regardless of color.
2) The price of US$ 57,541,779 is also the world record price for any blue diamond sold at an auction, previously held by the 12.03-carat, cushion-cut, flawless, fancy-vivid blue, "Blue Moon of Josephine Diamond," that sold for US$ 48.4 million at Sotheby's Geneva Magnificent Jewels Sale held in November 2015.
3) The price-per-carat world record for a blue diamond of US$ 4,023,275 is still held by the "Blue Moon of Josephine Diamond," that sold for US$ 48.4 million at Sotheby's Geneva Magnificent Jewels Sale held in November 2015. The price-per-carat of the "Oppenheimer Blue Diamond" works out to US$ 3,932,968 which is the second highest ppc-value for a blue diamond.
Related :-
External Links :-https://www.christies.com/lotfinder/Jewelry/the-oppenheimer-bluea-sensational-coloured-diamond-ring-5990891-details.aspx?lid=1
https://www.miningweekly.com/article/mystery-of-the-origins-of-the-oppenheimer-blue-2016-06-17
References :-
1. Christie's Press Release - The Oppenheimer Blue - The Largest Fancy Vivid Blue Diamond Offered at Auction - Geneva, 31st March 2016.
2. Christie's Press Release - 25th April 2016 - Magnificent Jewels, Including Superb Jewels from the Collection of H.S.H. Gabriela Princess zu Leiningen & The Oppenheimer Blue Diamond. Geneva 18 May 2016.
3. christies.com features - The Oppenheimer Blue Diamond - 7197 - 3.aspx
4. christies.com features - The Oppenheimer Blue Results - 7395-3.aspx
5. 14-Carat Oppenheimer Blue Diamond Earns 'World's Most Expensive' Title, Fetches $57.5 Million - Roberta Naas, forbes.com
6. Most Expensive Jewel Ever Auctioned: 'Oppenheimer Blue' Diamond Sells for History-Making $57.5 Million - Anthony DeMarco, forbes.com
7. THE OPPENHEIMER BLUE, A SENSATIONAL COLOURED DIAMOND RING - Lot 242 - Geneva Magnificent Jewels - Sale 1415 - 18 May 2016, Geneva. www.christies.com lot finder.
8. Philip Oppenheimer, Chairman Of Diamond Cartel, Dies at 83 - by Richard W. Stevenson - The New York Times - October 20, 1995.
9. Mystery of the origins of the Oppenheimer Blue - by Jade Davenport - CREAMER MEDIA CORRESPONDENT - CREAMER MEDIA'S MINING WEEKLY.
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