Since 1958, what almost certainly is the world’s most famous diamond been on public display at the Smithsonian Museum of Natural History in Washington, D.C. Surprisingly for many of the millions of museum goers who traipse past its display case each year, it does not conform to the image that they generally have of a diamond, because of its color, which is a dark grayish blue.
It is believed that the stone, which later became known as the Hope Diamond, was discovered at the Kollur mine in Golconda, India. Its recorded history began in the early 1660s, when the French traveler Jean Baptiste Tavernier purchased a 112.2-carat, crudely cut stone he described as a “beautiful violet.”
Tavernier sold the diamond to King Louis XIV of France in 1668 and it was then recut, resulting in a 67.1-carat stone that became a centerpiece of the French crown jewels. It disappeared in September 1792, during the turmoil that followed the French Revolution, but turned up in London some 40 years later, and then changed hands several times during the century that followed. One of its owners was a certain Henry Philip Hope, from whence it got its name.
Blue diamonds are exceedingly rare, constituting less than one-tenth of a percent of all fancy colored diamonds. The blue color is the result of the presence of boron atoms in the carbon crystal lattice of the stone. Most blue diamonds are Type IIb, which means that are devoid of the nitrogen atoms that tend to provide a yellowish hue. Extremely rare Type Ia blue stones, which do include nitrogen, sometimes provide the stones with a pale green appearance.
Only a handful of mines are known to have yielded fancy blue diamonds, among the them the Kollur mine in Golconda, the Letšeng mine in Lesotho, and the Karowe mine in Botswana. But the most prolific source by far has been the Cullinan mine in South Africa, which today is owned by Petra Diamonds
Their unique color and rarity make natural fancy blue diamonds among the most sought-after gemstones in the world, with the Natural Color Diamond Association reporting that the average price per carat for stones have increased 12 percent to 17 percent per annum over the past decade.
They also have yielded some of the most spectacular results seen at auction. In May 2016 the 14.62-carat “Oppenheimer Blue,” sold for $57.6 million, setting at the time a world record for any gem. The previous record was held by the “Blue Moon Diamond”, which sold at Sotheby’s for $48.6 million in November 2015, and was renamed by its Hong Kong owner stone the “Blue Moon Josephine.”
Together with the Hope Diamond, there are a handful of other famous fancy blue diamonds. They include the Tereshenko, a 42.9-carat pear shape stone named after its owners, the Tereshenko family, who were sugar barons in pre-communist Russia; the 31.1-carat Wittelsbach-Graff, which it is believed may have been cut from the same rough stone that produced the Hope; and the Winston Blue, a 13.2- carat flawless fancy vivid blue pear shape diamond that was purchased by Harry Winston in 2014 for $23.8 million.
MID House of Diamonds is of the world’s preeminent suppliers of loose fancy-colored diamonds, with a large and varied stock that includes blue stones. Because it is a world of which many diamond buyers are less familiar, with different pricing patterns and grading standards, MID invites you to speak with one of the fancy color experts on its team.