Moussaieff Jewelers' Unnamed Blue Diamond

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Origin of name

The 6.04-carat unnamed blue diamond set in a ring was purchased by Moussaieff Jewellers at a Sotheby's auction held in Hong Kong, on 8th October 2007, in a sale that created history by breaking the 20-year old world record for price per carat paid for a diamond at an auction, previously held by the Hancock red diamond. The diamond remains unnamed, and until such time it is christened we can refer to it as the Moussaieff Jewelers' unnamed blue diamond.

Characteristics of the diamond

The diamond is a 6.04-carat, fancy vivid blue, internally flawless (IF) diamond, with a square emerald-cut. Fancy vivid is the highest color grade for any color, and internally flawless is the highest clarity grade that can be achieved. The cut of the diamond is also a perfect square emerald-cut. The diamond may qualify for a triple zero certificate under the AGS (American Gem Society) grading system because of its ideal cut, ideal color, and ideal clarity. It is a combination of these three characteristics that caused this unique diamond to break the 20-year old world record for price per carat paid for a diamond at an auction, in spite of its relatively smaller size.

In the list of famous blue diamonds given below the Moussaieff Jewelers' unnamed blue diamond occupies the 13th position.

The 6.04-carat unnamed blue diamond

The 6.04-carat unnamed blue diamond

List of famous blue diamonds



carat weight


1 Copenhagen Blue Diamond 45.85 fancy blue
2 Hope Diamond 45.52 fancy dark grayish blue
3 Tereschenko 42.92 fancy blue
4 Wittelsbach 35.56 fancy intense blue
5 Sultan of Morocco 35.27 fancy grayish blue
6 The Blue Heart 30.82 fancy intense blue
7 The Heart of Eternity 27.64 fancy vivid blue
8 Transvaal Blue 25.00 unknown color grade
9 Unnamed Blue-Siba Corporation 20.17 fancy blue
10 The Blue Empress 14.00 unknown color grade
11 The Begum Blue 13.78 fancy vivid blue
12 The Blue Magic 12.02 fancy vivid blue
13 Graff Blue 6.19 fancy blue
14 Moussaieff Jewelers' unnamed blue diamond 6.04 fancy vivid blue

The Moussaieff Unnamed Blue Diamond is a rare Type IIb diamond. It is Type II because of the absence of nitrogen impurities or presence of nitrogen in undetectable quantities. Diamonds that contain detectable quantities of nitrogen impurities are known as Type I.

The diamond is Type IIb, because instead of nitrogen it contains trace quantities of another impurity, boron, which imparts the blue color to the diamonds. Boron also causes the diamonds to become semi-conducting, a property that can be used to distinguish between a natural blue diamond and an artificially enhanced blue diamond, which is non-conducting. Diamonds that do not contain any impurities at all, whether nitrogen, boron or hydrogen are known as Type IIa.

The occurrence of Type I diamonds in nature is almost 98 %, but the occurrence of Type II diamonds is only 1-2 %. The occurrence of Type IIa diamonds is 1-2 % in nature, but the occurrence of Type IIb diamonds is less than 0.1 %. Thus Type IIb diamonds are extremely rare in nature.


The early history of the diamond such as the country and mine of origin, the date of discovery, the original owners of the diamond, etc, are all not known, but given the fact that the diamond is of recent origin we can safely predict its source. The only diamond mine in the world producing blue diamonds of significant size and quantity, in the 20th century was the Premier Diamond Mines of South Africa. Thus the 6.04-carat blue diamond most probably would have originated in the Premier Diamond Mines of South Africa.

The owner of the diamond was an anonymous Asian collector, who had given the diamond to be auctioned at Sotheby's of Hong Kong, at one of its biannual sales. The rare diamond came up for sale on Monday, October 8, 2007, at the Sotheby's biannual sale in Hong Kong. The pre-sale estimate of the diamond was HK $ 48 million equivalent to US $ 6.19 million.

Most expensive gemstone in the world per carat

The bidding for the diamond was very intense with several bidders keen in acquiring the rare diamond. Finally the hammer was brought down in favor of Alisa Moussaieff for a record breaking sum of HK $ 61.9 million equivalent to US $ 7.98 million, much above the pre-sale estimate of US $ 6.19 million, making it the most expensive gemstone in the world, per carat, sold at an auction. The price per carat fetched by the diamond works out to US $ 1.32 million, which smashes a 20-year old world record held by the Hancock Red diamond which sold for US $ 926,000 per carat in 1987. Moussaieff Jewelers, based in London has a reputation for acquiring very rare and costly gems, such as the 5.11-carat Moussaieff Red diamond, the world's largest red diamond, which they acquired in the year 2002 for US $ 8 million. It is said that Alisa Moussaieff had been obsessively watching the rare blue gem change hands for more than two decades, until she had the opportunity of owning it, when it came up for auctions at Sotheby's in October, 2007.

After the auctions Alisa Moussaieff said that it was the rarity of the stone combined with its luster, that made the stone irresistible. "It seems the blue diamond mines are extinct - nothing is coming out from mother earth any more. I have stopped seeing any from South Africa,"she said. "It's the color, purity and "the life"of the stone. "The life"of the stone is the water, the shimmer inside the diamond. It's cut and the number of carats may appear on the certificate, but "the life"you have to see in the diamond."In a clear reference to the size and quality of the diamond, she further commented that, "size is not always what matters, what matters is quality."

Some famous blue diamonds

Blue diamonds have long fascinated and captivated the rich and the powerful, monarchs and dictators. The most celebrated of all blue diamonds is the Hope diamond and among the powerful rulers and the extraordinarily rich figures who had the fortune or misfortune of owning this diamond are King Louis XIV, King Louis XV, King Louis XVI, Queen Marie Antoinette, Henry Philip Hope and other members of the Hope family, Sultan Abdul Hamid II of Turkey and Evalyn Walsh McLean. Harry Winston acquired the infamous Hope Diamond when Evalyn Walsh's estate was put up for sale, and later donated it to the Smithsonian Institution.

The 45.52-carat Hope diamond is the largest blue diamond in the world whose whereabouts are known. The 45.85-carat, emerald-cut Copenhagen Blue diamond, that originated in the Jagersfontein mine of South Africa, is slightly bigger than the Hope diamond, but after the diamond was exhibited in Copenhagen, the capital city of Denmark, in 1960, the whereabouts of the diamond are unknown, and perhaps remains hidden in the vaults of a private collector.

The 42.92-carat Tereschenko blue diamond was owned by the famous Tereschenko family of Russia, who were industrialists, entrepreneurs and philanthropists in pre-communist Russia. The Tereschenko diamond was purchased by Robert Mouawad in 1984 at a Christie's auction in Geneva.

The 35.56-carat Wittelsbach blue diamond had been in the possession of the Wittelsbach family, the German noble family that provided the rulers of Bavaria, from the year 1722 until the abdication of the last king in 1918. The diamond was sold in 1931, re-discovered in 1962 and finally sold to a private collector in 1964.

Occurrence of blue diamonds

The main source of blue diamonds in the world before the 18th century was the famous Kollur mines of Golconda, in Southern India. The historic diamonds such as the Hope diamond, the Tereschenko diamond, the Wittelsbach diamond, and the Sultan of Morocco diamond, all originated in the mines of Golconda.

However after the discovery of diamonds in South Africa in the late 19th century, the main source of blue diamonds in the world became the Premier Diamond Mines of Transvaal, South Africa. The Blue Heart, the Heart of Eternity, the Transvaal blue and all other blue diamonds in the above list below No. 6, originated in the Premier Diamond Mines of South Africa. Besides this, the eleven blue diamonds that was exhibited as part of the De Beers Millennium Diamond Collection together with the Millennium Star diamond at the Millennium Dome in London, throughout the year 2000, also originated in the Premier Diamond Mines. However, it took almost 10 years to put together the collection of 11 blue diamonds for the exhibition. This gives an indication as to the rarity of existence of blue diamonds. It has been reported that only one significant blue diamond is mined in the Premier Diamond Mines every year, out of all the rough diamond production from the mines for an year. But, presently blue diamonds are even getting scarcer, and as Alisa Moussaieff had said it is difficult to see any new blue diamond coming out of South Africa. It appears that blue diamonds may become extinct, unless a new diamond mine producing blue diamonds like the Premier Diamond Mines, is discovered. This explains the demand for natural blue diamonds and the enhanced price realized for the 6.04-carat unnamed blue diamond, at the Sotheby's auction

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