A diamond is a gem that pertains to the cubic system, it’s mainly composed of carbon and has a hardness of 10 on the Mohs scale (that’s the highest grade) which means that a diamond can only be scratched by another diamond.

For most of you, "diamond" refers to a white or colorless stone. That being said, did you know colored diamonds called "fancy diamonds" also exist? In fact, diamonds come in all colors: pink, yellow, orange, red, violet, green...

White diamonds are graded from D to Z depending on their color, D being the purest color, with no yellow tones, and Z being the most yellow-tinted color. However, for some experts, M to Z diamonds are considered yellow-tinted or light yellow diamonds, rather than yellow-tinted white diamonds.

Color is one of the 4 criteria diamonds are subjected to, otherwise known as the "4Cs": Carat, Cut, Color and Clarity.

 

Causes of diamond colors

The stronger the color intensity of a "colored" diamond is, the more expensive it will be. The most sought-after intensity being "fancy".

Gradation of diamond color intensity, copyright I-Diamants

 

The rarest colored diamonds are: red diamonds, intense green diamonds and intense blue diamonds.

The most common colored diamond is yellow. In fact, the yellow hue or color in diamonds is due to one of the most common compounds (apart from carbon): nitrogen. It is a part of the composition of most diamonds.

Pink and brown diamonds appear as a result of a deformation of their crystalline structure due to the very high pressures to which they are subjected. Experts aren't sure what causes the color of red diamonds, but one hypothesis is that it's the same as for pink and brown diamonds. The gem then reflects more red light proportionally to the deformation it has undergone.

A diamond will turn green following its exposure to radioactive uranium, which will alter the disposition of elements in the crystal lattice.

A diamond will turn blue if boron enters the stone's crystalline structure. This color might also be due to exposure to radiation or the presence of nitrogen.

Finally, the presence of hydrogen could be linked to the color of purple diamonds.

As for black diamonds, their hue is due to the presence of numerous inclusions (graphite, pyrite or hematite) or to the graphitization process (transformation into graphite).

A colored diamond can be of any color of the rainbow, which can be obtained through a combination of the above-mentioned causes.

Color wheel, copyright Taylor & Hart

 

Famous colored diamonds

One of the most famous blue diamonds - if not most famous - is the Hope diamond. Brought back from Golconde (India) by Jean-Baptiste Tavernier and sold to Louis XIV in 1668, it was stolen during the Hôtel de la Marine robbery in 1792. It reappeared in London 20 years and a few days after the statute of limitations had expired, and was passed down from owner to owner. Among them were Pierre Cartier, King Louis XVI, the Hope family - after whom it was named - and the famous jeweler Harry Winston, who donated it to the Smithsonian Institution in Washington over 60 years ago.

It’s an exceptional fancy blue-gray diamond that has been cut several times and originally ranged from 112 to 115 carats, currently weighing 45.52 carats. The Hope diamond has exceptional gemmological characteristics, such as its red phosphorescence (after exposure to UV light, it glows for more than a minute) and its very high boron concentration - the cause of its color -.

The Hope Diamond, copyright Smithsonian Institution

 

The Tiffany yellow diamond was discovered in 1877 in the famous Kimberley diamond mine in South Africa. It was sold to Tiffany’s founder Charles Lewis Tiffany as a 287.42-carat rough. After being cut, this gem was presented to the public at several exhibitions before being used in creations by the jeweler. This diamond has been worn by 4 women: Mary Whitehouse at the Tiffany Ball, Audrey Hepburn in the movie Breakfast at Tiffany’s, Lady Gaga at the Oscars and Beyoncé in the About Love advertising campaign. It has also been set in two pieces of jewelry made by the famous Jean Schlumberger, whose necklace was featured in Breakfast at Tiffany’s.

The Tiffany Diamond, copyright Only Natural Diamonds

The Tiffany diamond around the neck of Lady Gaga, Audrey Hepburn and Beyoncé, copyright People

 

The golden jubilee is a yellow-brown diamond and the world's largest cut diamond at 545.67 carats. It was discovered in the Cullinan mine in South Africa in 1985. In 1995, it was purchased by Thai businessmen, then presented to the King of Thailand in 2000, where it remains to this day.

The Golden Jubilee Diamond, copyright Astteria

 

The Dresden green diamond entered the collection of Frederick Augustus II, then King of Saxony, in 1741. It was later set in the Order of the Golden Fleece and is still there. It was kept in Auguste Le Fort's treasure room in the Green Vault at the Staatliche Kunstsammlungen in Dresden. On November 25, 2019, one of the biggest robberies ever took place when men infiltrated the museum and stole numerous jewels and artworks worth over 100 million euros. Fortunately, the Dresden green had been loaned to the Metropolitan Museum of Art in New York, and therefore was not stolen. Weighing 40.7 carats, it’s the world's largest green diamond.

The Dresden Green Diamond, copyright Only Natural Diamonds

 

The Pink Star diamond was mined in 1999 by the De Beers company, it weighed 132.5 carats uncut. It’s a fancy vivid pink diamond with maximum purity "internally flawless" that weighs 59.6 carats. It was sold in 2017 by Sotheby's to Chow Tai Fook, a chinese jeweler, for $71.2 million, making it the most expensive diamond ever sold in the world. Most pink diamonds were extracted from the famous Argyle mine in Australia which closed in 2020.

The Pink Star Diamond, copyright Only Natural Diamonds

 

At a recent Sotheby's auction in Geneva, an exceptional diamond was sold: the Laguna Blu, a blue diamond set in a Bulgari ring. It fetched 23.2 million euros. It’s a fancy vivid blue, pear-cut and 11.16 carats diamond. It had not been seen since 1970, and was re-inaugurated at the Met Gala in 2023 by Priyanka Chopra before being sold in Geneva.

The Laguna Blu Diamond, copyright Only Natural Diamonds

 

If you are interested in diamonds, do not hesitate to discover what Les Pierres de Julie has to offer in store...

We are also available for any free expertise of your jewelry, for that you can send an email with your photos to contact@lespierresdejulie.com.

Whether you're interested in buying a piece of jewellery or a stone, a free jewelry appraisal or jewelry resale, Pierres de Julie welcomes you to its Parisian boutique in the Village Suisse, a stone's throw from the Ecole Militaire and the Esplanade des Invalides.