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THE AMSTERDAM DIAMOND
An unmounted modified pear-shaped fancy black diamond weighing 33.74 carats, in a blue leather fitted case
With certificate 10565041 dated 18 January 1999 from the Gemological Institute of America stating that the diamond is fancy black, natural colour

With certificate and appendix 9911078 dated 6 December 1999 from the Gübelin Gemmological Laboratory stating that the diamond is black, natural colour

With certificate 10237 dated 27 September 2001 from the Gem Tech Lab, Geneva, stating that the diamond is black of natural coloration

The above certificate accompanied by an annex stating the following:
This historic diamond called the Amsterdam is one of the very few monocristalline black diamonds that can be described today as: "of natural coloration".
This gem is of an unusual size for the type. It owes its colour to the presence of small graphite grains mainly located in the feathers, and to diffusion mechanisms similar to those observed in storm clouds.
This diffusion is generated by the presence of very numerous cristalline microdiscontinuities whose microscopic examination shows that they do not contain graphite.
The gem was cut in 1972 by the firm D. Drukker & Sons of Amsterdam. The cutting has been executed very carefully, without excessive heat, and has not generated pyrolitic graphites that may have intensified the colour of the stone.
This gem can be considered as representative of the best quality in black diamond.
Literature
Ian Balfour, "Famous Diamonds", Christie's, Manson and Woods Ltd., London, 1997, page 292

Lot Essay

Black diamonds owe their colour to a large number of very small carbon inclusions which absorb nearly all the light falling on the stone. Most black diamonds are therefore translucent to opaque against light and often have noticeable grey spots where carbon formation is not even. When polished, the surfaces of black diamonds are usually pitted.
This remarkable diamond, which originally was a large piece of mine bort, was destined to be broken up into smaller pieces or crushed into diamond powder. Its value at that time was a mere US$6.00 per carat. Fortunately, the cleaver was so impressed by its hardness and black intensity of its splinters that it was decided to cut and polish it as a gem.

Found in South Africa, it was purchased by Amsterdam diamond merchants D. Drukker & Sons in 1972. The diamond was then painstakingly fashioned from its original 55.85 carats into a pear-shaped stone of 33.74 carats with a total of 145 facets. It was christened The Amsterdam Diamond in honour of the 700th anniversary of the city of Amsterdam. This gem has since been exhibited on numerous charitable occasions and was even valued at a staggering US$2 Million in 1991. The only other example of a black diamond in this price bracket would be the rectangular-cut diamond of 489.07 carats sold recently at auction for US$1.7 Million or US$3,500 per carat.

Contrary to most black diamonds, The Amsterdam Diamond is remarkably opaque, even under optimal lighting and has near perfect polish and proportions for a black diamond, therefore giving it a lustre seldom seen in large black diamonds, making it a truly collectable gem.
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