(This 163.41 carat D-colour, flawless diamond is the largest of its kind on earth - source: Christie's)

In what is set to be the most exciting gem auction of 2017, the largest D-colour flawless diamond ever put under the hammer, at 163.41 carats, will be on sale on 14th November at Christie's Geneva. Said to be 'the most beautiful diamond in the world,' it is currently set into an asymmetric necklace created by de Grisogono. The stone originates from a 404.20 carat rough diamond that was won from the ground on 4th February 2016 in eastern Angola. In itself the 'parent' stone was the 27th largest rough white diamond ever found and the largest ever discovered in Angola. It was sent to the GIA (Gemmological Institute of America) in New York for spectrographic testing, where it was confirmed as D-colour (the 'whitest' on the D-Z scale) and Type IIA (the best transparency and colour combination). The GIA scientists working on this stone went on record to say "the extreme rarity of a diamond of this quality cannot be overstated," demonstrating the scientific importance and uniqueness of the find. Once it had received its certification from the GIA, it was transported to the New York diamond district and the impressive glass windowed workshop of the Julius Klein Group on 5th Avenue and 47th Street. Here a team of 10 highly skilled cutters and polishers transformed the 404.20 carat rough stone (the largest they had ever worked) into the final 163.41 polished gem we see today.

New York, NY

(New York diamond district, 5th Ave & 47th St - the largest gem & jewellery centre in the world)

Gemmological expert Isaac Barhorin analysed the stone in close detail, in various light conditions, to inspect every surface of the gem and its interior with a binocular microscope in order to prepare it for the cutting process. He explained: "I start by seeing what the stone can give, I am looking for cracks, grainy spots, feathers and carbon spots, and I will build up the stone around these. The goal is to reach an internally flawless stone." Despite the high technology that is employed to ensure each gem is cut to its fullest potential, a very low technology felt tip pen was used to mark out the initial cutting points! Following months of detailed analysis in June 2016 one of the most experienced diamond cutters, 80 year old master diamond cleaver Ben Green, set to work using the skills and experience he has gained over more than half a century in his profession. Having cut his first stone in 1964, Green is now regarded as the foremost cleaver in the world. He offered the following explanation for the first stage: "diamond is like wood, it has a grain. You can saw it or divide it along the grain." With great skill and the use of the time honoured tools of the trade, including dark cement to hold the diamond in situ on a wooden base, a loupe and two flat blades, he proceeded to split the stone precisely in two.


(The 404.20 carat 'parent' stone was the largest ever worked by the Julius Klein Group in New York)

However, this was only the start of the process. Following the division of the stone in two, the cut had to be completed with painstaking precision on the polishing wheel over many weeks. In order to cut each individual facet, the rough stone must be carefully rotated by hand on a spinning diamond-tipped disc and this must all be done by eye. This process took more than six months, after which the final 163.41 carat, emerald-cut stone was complete. All that remained was to fashion the diamond into a piece of fine jewellery. This honour fell to the Geneva workshop of jewellery legend de Grisogono in December 2016. Here the founder, Fawaz Gruosi, and his team of five master jewellers set about the task with verve and flair. Gruosi's reputation certainly precedes him; he was recently described by jewellery historian Vivienne Becker in the book 'Daring Creativity,' which analyses the history of de Grisogono, as "a reverent revolutionary with a deep, intuitive understanding of jewellery, a respect for the noble arts of the goldsmith and the jeweller, and an unfettered passion for gemstones." Despite his vast experience, 'the most beautiful diamond in the world' gave Gruosi, in his words, "quite a big headache but I am crazy enough to break a jewel apart and start again if I am not happy with it."


(The finished article containing 18 emerald-cut flanking stones set above the large centre stone)

Gruosi went on to say: "I never thought I would work with a 163.41 carat diamond of this quality. I have never had a problem finding creative ideas but this time there was the immense pressure of 'dressing' such an amazing diamond. I couldn’t do something very simple or that has already been seen. I needed a design that is outside-the-box." His elegant solution to the problem: an asymmetric necklace containing 18 emerald-cut diamonds, flanking the 163.41 carat centre stone, referred to by Gouris as the "queen, surrounded by an haute couture dress." The design was the work of a collaborative effort between Patrick Affolter, head of de Griogono's high jewellery atelier, and a team of crafts people. The resulting piece was showcased in Hong Kong, London, Dubai and New York, prior to its arrival in Geneva for the Magnificent Jewels auction on 14th November. The piece was notable for the fact that the centre stone was designed to be detachable, enabling it to be re-mounted into another item of jewellery. When asked to comment on the piece Rahul Kadakia, International Head of Christie's Jewellery department, stated: ‘in our 251 year history, Christie’s has had the privilege of handling the world’s rarest and most historic diamonds, this sensational gem propels de Grisogono into a class of its own."


(Christie's Magnificent Jewels auction attracts the sale of some of the world's most valuable gems)

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