"Blue diamonds that gemmologists ought to be familiar with, unveiling the biggest examples."
In the realm of precious gems, blue diamonds stand out for their rarity and breathtaking beauty. These unique stones owe their striking colour primarily to the presence of boron, an element that becomes part of the diamond's crystal structure under specific geological conditions.
Blue diamonds are formed in the deepest parts of the Earth's interior, where boron impurities are more likely to be present. The formation process involves high pressure and temperature conditions, boron incorporation, crystal growth, and the eventual emergence of the diamond to the Earth's surface through volcanic eruptions or other geological events.
One of the most famous blue diamonds is the Hope Diamond, which owes its colour to boron impurities. Other notable examples include the Heart of Eternity and the Orlov Diamond.
While natural blue diamonds are extremely rare and valuable, synthetic blue diamonds can be created through laboratory processes. However, these do not involve boron incorporation in the same way as natural diamonds. Instead, they may use other methods to achieve a blue colour, such as irradiation or doping with boron during the growth process in a laboratory setting.
Some of the most remarkable natural blue diamonds include the Farnese Blue, a 6.16 carat fancy dark grey-blue diamond with provenance spanning European royal families. The Memory of Autumn Leaves pink diamond, at 16 carats, VVS2 clarity, and Type IIa, is another noteworthy gem.
The Blue Moon of Josephine holds the per-carat price record for a blue diamond, with a price of US $4,028,941 per carat. This diamond was renamed by its new owner as a tribute to his daughter. The Blue Moon of Josephine was sold by Sotheby's in 2015.
The Zoe Diamond, a 9.75 carat pear-shaped fancy vivid blue stone, achieved an impressive US $32.6 million at auction in 2014. The Sky Blue Diamond, an 8.01 carat square-cut VVS1 fancy vivid blue diamond, was sold at Sotheby's Geneva in 2016 for US $17 million, more than US $2 million per carat.
The Millennium Blue, a 10.10 carat, oval-shaped, internally flawless stone, was sold at Sotheby's Hong Kong in April 2016 for US $31.8 million. The Wittelsbach-Graff Diamond, a 35.56 carat fancy deep greyish blue diamond, is believed to come from India's famous Golconda mines.
The De Beer Cullinan Blue Diamond, a Type IIb diamond representing less than 0.5% of all diamonds, was discovered at the Cullinan Mine in South Africa. This 15.10 carat step-cut blue diamond was sold at Sotheby's Hong Kong in April 2022 for US $57.4 million.
The Memory of Autumn Leaves blue diamond, at 14.54 carats, internally flawless and Type IIb, is another extraordinary example of a blue diamond.
These rare and valuable blue diamonds continue to captivate the world with their beauty and rarity, offering a glimpse into the secrets of the Earth's interior and the wonders of gemstone formation.
A diploma in gemmology might provide insights into the unique formation process of blue diamonds, including their boron impurities and the high pressure-temperature conditions that give them their breathtaking beauty. Despite their Casino-and-gambling appeal, the value of synthetic blue diamonds pales in comparison to the authentic ones, which are highly sought after by collectors and gemstone enthusiasts alike.
