Blue diamond: a rare colour, a fascinating story

Why is the blue diamond so fascinating?

The blue diamond is one of the rarest and most captivating gemstones in the world. Unlike other coloured diamonds, its natural blue hue comes from the presence of boron, a chemical element that becomes part of the crystal structure while the diamond forms. This exceptional and extremely rare geological phenomenon gives the blue diamond its deep, spellbinding colour, which has fascinated collectors and jewellery lovers for centuries.

A unique formation deep within the Earth

Blue diamonds form like all diamonds: under high pressure and temperature, several hundred kilometres below the Earth's surface. What sets them apart is the incorporation of boron atoms into their crystal structure as they form. This boron changes the way the diamond absorbs and reflects light, creating that distinctive blue hue. The higher the boron content, the more intense the colour.

This natural incorporation of boron is extremely rare: it is estimated that fewer than 0.1% of mined diamonds show a natural blue hue. This extraordinary rarity explains why blue diamonds are among the most precious and sought-after stones in the world.

Shades of blue: a rarity in itself

Blue diamonds come in a range of hues from pale blue to intense blue, sometimes with violet or grey overtones. On the GIA (Gemological Institute of America) scale, they are graded by intensity: Fancy Light Blue, Fancy Blue, Fancy Intense Blue and the extremely rare Fancy Vivid Blue.

The colour may be even or varied, and the more vivid and pure the hue, the rarer and more precious the stone. Lab-grown blue diamonds now reproduce these magnificent shades, but those whose colour is 100% natural (certified by recognised laboratories) fetch dizzying prices on the market. At Lauredi, every blue diamond ring is set with a lab-grown diamond, giving you this colour without the price of a natural stone.

The blue diamond in history: a few iconic examples

Among the few known blue diamonds, three stand out for their exceptional history and rarity:

The Hope Diamond:

Probably the most famous of all, this 45.52-carat diamond is on display at the Smithsonian Institution in Washington. Its deep blue colour with violet overtones and its eventful history make it a legendary stone. Originating from the Golconda mines in India, it was once known as the "French Blue" and belonged to the French Crown Jewels before being stolen during the French Revolution. Recut and renamed, it passed through the hands of several owners before the jeweller Harry Winston donated it to the American museum in 1958.

The Blue Moon of Josephine:

This 12.03-carat intense blue diamond is considered one of the most valuable ever sold at auction. Discovered in the Cullinan mine in South Africa in 2014, it was sold by Sotheby's in Geneva in 2015 for a record $48.4 million, more than $4 million per carat. Bought by a Hong Kong billionaire for his 7-year-old daughter, the diamond stands out for its exceptionally pure, vivid blue colour, graded Fancy Vivid Blue by the GIA.

The Wittelsbach-Graff:

This historic 31.06-carat diamond dates back to the 17th century and was part of the Bavarian Crown Jewels. Acquired in 2008 by the jeweller Laurence Graff for $24.3 million, it was slightly recut to enhance its brilliance while preserving its exceptional weight. Its Fancy Deep Blue colour and royal history make it one of the most prestigious diamonds in the world.

These rare stones are admired not only for their beauty but also for the stories they carry across centuries and continents.

How a blue diamond is assessed

The value of a blue diamond is assessed on several criteria:

Hue and intensity: the deeper and more even the colour, the rarer the stone
Clarity: as with all diamonds, inclusions affect the value, but less than colour does
Carat weight: stones above 1 carat are extremely rare
Cut: a cut that enhances the colour and shows it at its best increases the value
Natural origin: certified by an independent laboratory such as the GIA or IGI

How much is a blue diamond worth?

Natural blue diamonds are among the most expensive stones in the world. A certified stone, even a small one, can reach astronomical sums. In 2016, the 14.62-carat Oppenheimer Blue sold at Christie's for $57.5 million, setting what was then a world auction record for a diamond. In 2015, the 12.03-carat Blue Moon of Josephine reached $48.4 million, more than $4 million per carat, a price per carat never matched for a diamond. The price varies with the intensity of the colour and the other criteria mentioned, but also with origin: blue diamonds from the Cullinan mine in South Africa or from Golconda in India are particularly prized for their exceptional quality.

See our available blue diamonds

Why choose a blue diamond?

Beyond its rarity, the blue diamond carries strong symbolism: depth, serenity, wisdom. It is a stone that appeals to those seeking originality and refinement. Choosing a blue diamond means opting for a touch of timeless elegance that rises above passing trends. It is also an increasingly popular choice for a diamond engagement ring that stands out from the ordinary.

And while the price of natural stones remains prohibitive for most people, there is now a credible alternative: the lab-grown blue diamond. Thanks to remarkable technological advances, these laboratory-created gems offer a striking blue colour while meeting demanding ethical and aesthetic standards. This modern, committed option is a wise choice for anyone who wants to own this exceptional stone without compromising on beauty or values.

Conclusion

The blue diamond brings together science, history and aesthetics. Its natural rarity, its unique formation process and its incomparable beauty make it an exceptionally coveted stone. Whether you are passionate about gemmology or simply looking for an original stone for an important moment in your life, the blue diamond deserves your attention. Its spellbinding hue will continue to fascinate and inspire for generations to come.