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The Incomparable Diamond

The Incomparable is the third largest cut diamond in the world. It was discovered as a piece of rough weighing an incredible 890 carats in the town of Mbuji Mayi in Zaire (now the Democratic Republic of Congo) in the 1980s. Incredibly, it was discovered by a young girl playing outside her uncle's house in a pile of rubble that had been discarded by a nearby diamond mine as being too bulky to be worth processing for diamonds! The little girl's uncle sold it on to some local African diamond dealers who in turn sold it to a group of Lebanese diamond buyers in Kinshasa. It was then purchased in Antwerp by De Beers and sold to Donald Zale, chairman of the board of the Zale Corporation, the Dallas-based jewellery store chain, in partnership with Marvin Samuels of the Premier Gems Corporation and Louis Glick, both prominent figures in the New York diamond industry. The finished stone was finally unveiled in November 1984 as part of Zale's 75th Diamond Anniversary.

Marvin Samuels

But before all that, the stone had to be cut, a job that was overseen by Mr Samuels. The rough stone was extremely irregular, thicker at one end, narrower at the other, pitted and sunken on one side, ridged on the other. One piece of good news at least, was that, after polishing a window on the stone to look deep within, it could be seen that it was largely free from inclusions.

Fancy brownish-yellow

It took four years of study and practice working on the smaller fragments that were chipped off the main stone to finally complete the project. The owners had at first hoped to surpass the size of the largest cut diamond in the world at that time, the Cullinan I which weighed 530.20 carats, although as work progressed it became clear that this would not be possible. But as more excess was removed from the exterior of the rough, it also became clear that the internal parts of the stone were in fact of a superior medium yellow as opposed to a darker brown. The final finished stone was eventually graded as “Shield-Shaped Step Cut, Internally Flawless clarity and Fancy Brownish-Yellow in colour”. It's final weight was 407.48 carats, the third largest cut diamond in the world. The stone appeared shortly afterwards at auction with Christie's in London where it was called the 'Golden Giant'. Bidding failed to reach the $20 million reserve and the diamond remained unsold, although history was made with the largest ever bid at that time for a single stone being placed at $12 million. In 2000 the diamond appeared on eBay with an opening bid of $25 million, but again it went unsold. It set another record for being the largest ever diamond to be offered on eBay, or indeed any other internet auction site.

Mouawad Incomparable Diamond Necklace

Some time after this it was purchased by the Mouawad jewellery house who incorporated it into the Mouawad Incomparable Diamond Necklace. The necklace was certified as the most valuable necklace in the world in 2013 with a vlaue of $55 million. The Incomparable is set in 18 ct yellow gold amongst some 229.52 cts of white diamonds.

Find out about the world's 2nd largest diamond.

If you have any diamonds that you would like to have valued then please contact Simon Rufus at Grand Auctions in Folkestone, Kent for a free auction valuation.