The world’s largest Fancy Vivid pink pear shaped diamond ever offered at auction at Sotheby’s in Geneva, the Unique Pink which sold for $31.6 million.
All gemstones and coloured diamonds have to be seen with the naked eye to gauge their colour, as the first visual impression is important. Taking the colour description from the certificate alone only gives you part of the story.
Pink diamonds can encompass a variety of hues, from purplish to orangey to reddish, and this diamond has a wonderful energetic pink that seems to display a slight tinge of red, making it indeed unique. Unlike other coloured diamonds where the hue is caused by the intrusion of another atom such as nitrogen or boron, with pink diamonds the colour occurs because of the distortion or stress in the crystal structure when it was formed millions of years ago.
The Unique Pink 15.38 carat diamond was cut by Cora International, a company known worldwide for producing rare diamonds of large sizes and vivid fancy colours. The task of cutting and polishing this rough crystal would have started with many months of deciding how to achieve the colour to its maximum potential, and there are only a very few cutters in the world who could take on this challenge.
There is an element of risk in cutting any diamond, and cutting a coloured stone is even more complicated as you want to make the colour as strong as possible by getting it to radiate from the middle of the stone. When cutting white diamonds, the opposite tactic is required to make them look colourless. It’s very difficult to gauge the eventual colour of a pink diamond while being cut on the wheel as they can heat up momentarily making them change colour, so the cutter will not see the true results until the diamond has cooled down.
The Gemological Institute of America grades nearly all of the world’s most important diamonds and of all the diamonds submitted to the laboratory each year no more than three per cent are classified as coloured diamonds. Less than five per cent of those coloured diamonds are predominantly pink. This stone is also classified as a Type IIa which is the most chemically pure type of diamond based upon the absence of nitrogen. Only two per cent of all diamonds mined display this exceptional transparency.
Apart from the new owner buying one of nature’s rarest gems he or she will be able to rename the stone, just to add to its uniqueness.