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.