
A superb fancy vivid Blue Diamond of 5.04ct and Diamond Ring was sold this month at an auction by Sotheby in Hong Kong for HK$81,796,000 or ~US$10.55 million.
The fancy vivid blue heart modified brilliant-cut diamond was flanked by two pear-shaped diamonds, mounted in platinum, size 4¾.
Accompanied by GIA report no. 12150222, dated 20 February 2020, stating that the diamond is Fancy Vivid Blue, Natural Colour, VS2 Clarity; further accompanied by a diamond type classification letter stating that the diamond is determined to be a Type IIb diamond.
‘…All the colours of flowers and foliage and even the blue sky and the glory of the sunset clouds, only last for a short time, and are subject to continual change, but the sheen and colouration of precious stones are the same to-day as they were thousands of years ago and will be for thousands of years to come. In a world of change, this permanence has a charm of its own that was early appreciated…’ – G.F. Kunz, 1913
Diamonds in essence are pure and simple in composition, requiring only one element as it crystalizes: carbon. However, as nature pressurizes on these very elements deep within the mantles of earth, numerous variables ranging from temperatures to surrounding environments affect the formation process. This is how diamonds obtain their variety in the full colour spectrum, as the structural impurities, inclusions and even radiation exposures allow the crystals to capture a myriad of colours that have been appreciated and treasured throughout the ages.

Among all fancy coloured diamonds, blue diamonds are one of the most famous diamonds throughout history. Early records can be traced back to the 17th century when Jean Baptiste Tavernier sold a dark blue diamond to King Louis XIV of France, which was originally called the Tavernier Blue, and then the French Blue as a part of the French Crown Jewels. Later the mystique of the famed Hope Diamond, which was purchased by Henry Phillip Hope in 1830, was only heightened when research studies showed that the Hope Diamond could potentially have been recut from the lost French Blue.

The distinctive hue of the blue diamonds is often attributed to the trace of boron within the crystal (Type IIb). It could sometimes also be a result of hydrogen (Type Ia) in the structures or even radiation exposures to the diamond, but this is rare and often results in having a greyish tone when graded. Because of its formation, every faceting process of a blue diamond demands extreme care and precision. The rough will likely be asymmetrical with colour zoning, which presents unique challenges to the cutter as they balance the best colour, carat weight and the type of cut for each stone.
Lot 1806 presents a heart-shaped fancy vivid blue diamond of 5.04 carats, which was determined to be a Type IIb diamond. Type IIb diamonds are usually free of nitrogen impurities, with boron in its crystal matrix that gives its stunning blue hue. The famed Hope Diamond is also classified as a Type IIb diamond.
Re-post with photos from Sotheby.com