The Incomparable Diamond

A whopping 890 carats in its rough form, the Incomparable Diamond is among the largest flawless diamonds ever discovered. It was found in the 1980s, by a young girl playing in a pile of building rubble outside her uncle’s house. The rubble had come from a nearly mine, and had been rejected for being too bulky to contain anything of value.

The Incomparable DiamondThe girl gave the stone to her uncle, who sold it to some local dealers; eventually, the rough piece found its way to Sir Philip Oppenheimer, a director of De Beers. He bought the stone in partnership with Louis Glick and Marvin Samuels. It was unveiled to the world in 1984, and was on display for a while at the Smithsonian Institution in Washington.

Cutting the diamond took four years of careful planning. The rough was an unusual shape, thick at one end and narrow at the other, with an irregular, sunken side that showed various pits, cavities and cracks. However, early inspections showed that the interior was free of any flaws.

They polishers were initially tempted to retain as much weight as possible, aiming to exceed the weight of the 530 carat Cullinan diamond. However, during the second year of the polishing operation, it became clear that this would not be possible.

Another interesting feature of the diamond was its colour, and how the colour was spread through the diamond; it had formed as a colourless centre, and at some point in its formation a thin skin of yellow had formed, and outside of that a further layer of smokey yellow/brown colour. As some sections were polished, the colour through the diamond lightened and improved.

The largest piece to come from the rough was a 407 carat shield shape step cut, christened a “Triolette” cut; this is the Incomparable Diamond. A further fourteen diamonds were also polished, weighing from 15.6 carats down to 1.33 carats. The Incomparable was graded by the GIA as Internally Flawless and Fancy Brownish-Yellow in colour.

The Incomparable was displayed in Paris in 2001 in the Natural History Museum, however it suffered in indignity of being displayed upside-down! Below is a facet diagram, showing the interesting and unusual nature of the cut.

The diamond was bought by Mouawad Jewellers, who mounted it in a spectacular necklace featuring 637 carats of diamonds; this was unveiled at a gem show in Doha in 2013. The Guinness Book of Records have recognised this as the most expensive necklace in the world, at a heart-stopping 55 million dollars. (Amazingly, this was broken in 2016 by Wallace Chan’s $200 million “Heritage in Bloom” necklace)

Below is a publicity video from Mouawad’s for the necklace, showing it in all its splendour! The close up of the diamond about twenty seconds into the video shows how lively and bright the stone is, testament to the quality of the cutting.