What are blue diamonds: how real and expensive they are

An expert guide to the world of natural blue diamonds.

What do you imagine thinking about diamonds? Luxuriously sparkling white stones, from Marilyn Monroe’s song in Gentlemen Prefer Blondes?

The world of natural diamonds is much wider and more diverse. These treasures exist in different colors: yellow, orange, pink, blue, green and purple. And among them, Blue Diamonds are considered one of the rarest and most valuable.

What are blue diamonds? Are they real?

Diamonds found in nature and containing a blue tint are considered to be Blue Diamonds. Although such stones are extremely rare, they are real – and they make collectors hunt all over the world.

Note that diamonds that have been artificially added blue color are not considered real Blue Diamonds. The difference between these two stones will be huge: it will primarily affect the price. A natural diamond will cost hundreds of times more than an artificially color-enhanced one.

Lab-grown Blue Diamonds also cannot be considered real. Outwardly, they will look like real ones, and the price will be slightly lower. However, such stones have no real value.

Origin of blue color in diamonds

Natural Blue Diamonds come from somewhere beneath the earth. They have been forming there for billions of years. Their color comes mostly from traces of boron in their carbon structure. The more boron – the more saturated a diamond is. However, boron is usually poorly presented in the layers where diamonds are formed. That is why Blue Diamonds are so rare.

However, sometimes it is caused by radiation exposure or hydrogen. Those gems that were exposed to radiation usually feature greeny blue shades, while those exposed to hydrogen demonstrate gray-violet and gray-blue tints.

Types of Blue Diamonds by color scale

The color characteristic is pretty complex in Blue Diamonds.

Their grading scale varies from faint blue, very light blue, light blue, fancy light blue, fancy blue, fancy intense blue, fancy deep blue and fancy vivid blue.

The key hue in such stones is necessarily blue. The most common secondary hues are green-blue and gray-blue. However, there are many color combinations to see in such diamonds.

The most beautiful and valuable stones are those that demonstrate pure blue color – without any added shades. However – surprisingly – pure blue diamonds of light color may be considered less valuable than stones of saturated and vivid green-blue or gray-blue colors.

As you can see, the intensity of the color is really important.

Rarity of Blue diamonds

While White and Yellow Diamonds are a common sight, Blue Diamonds are considered to be the rarest along with Pink and Red diamonds. The chance to find a Blue Diamond in a mine is as rare as 1 to 10,000. Those gems displaying clear vivid blue color are even rarer. Real natural treasures!

Blue Diamonds prices

Due to their scarcity, Blue Diamonds are extremely expensive. Their price depends on the color, intensity, cut, clarity, and weight – the scheme is the same as for all other diamonds. 

However, the color and its characteristics are the key factors. 

According to the statistics, light blue diamonds cost on average $15,700 per 0.25 ct, deep blue and vivid blue stones cost more – around $75,000 per 0.25 ct.  The higher and purer the color intensity and carat weight, the higher the price. 

For example, this 0.53 ct Fancy Intense Blue diamond costs around $180,000, this 2.02 ct diamond of Fancy Intense Blue color is on sale for about $530,000. Moreover, it was a blue diamond that once broke all the world records for price. It is called the Oppenheimer blue. Classified as Fancy Vivid Blue and weighing 14.64 ct, it was sold for incredible $58 million. 

Blue Diamond mines 

Natural Blue Diamonds are found only in three areas in the world: in Australia (the Argyle mine), South Africa (the Cullinan mine near Pretoria) and India. These mines normally excavate just several Blue Diamonds in a year. 

An interesting fact: once Blue Diamonds were even mined in the famous Indian Golconda mine. 

The most famous Blue Diamonds

There are several Blue Diamonds that drove the whole world crazy and that are still legendary. 

The Hope diamond

The Hope diamond of 45.52 ct is the most famous gem in the world. It has a dark history dating back for centuries. Found in India in the 17th century, this deep-blue stone has changed many owners, bringing misfortune to everyone. 

Initially, the rough Hope diamond weighed 115.16 ct. It was found by a French gem merchant called Jean-Baptiste Tavernier. He sold the stone to Louis XIV of France. The King decided to recut the diamond into a 68 ct French Blue gem. Unfortunately, this stone was stolen and reappeared already as a 45.52 ct stone named the Hope diamond.

Today, its value is estimated as $200 and $250 million.

The Wittelsbach-Graff diamond

The Wittelsbach-Graff diamond was passed through Austrian royalty and finally sold at an auction to Laurence Graff. It has one of the most interesting backgrounds. 

According to the legend, it was acquired in 1664 by King Philip IV of Spain as a gift to his daughter Margarita Teresa. After her marriage, the stone became a part the crown jewels of Austria and Bavaria.

In 1931 the Royal House of Wittelsbach offered the diamond for sale on Christie’s. However, it failed to reach the reserve price. In 2008 it was acquired by Laurence Graff for $23.4 million. At that time, it was the highest price ever paid at auction for a diamond. 

Later Graff decided to recut the stone and plunged the public into shock. Because of cutting, the stone lost around 5 ct. However, its color shade and clarity grade improved greatly. Later Graff sold the stone for at least $80 million.

Today, the Wittelsbach-Graff diamond weighs 31.06 ct and demonstrates the Fancy Deep Blue color.

The Oppenheimer blue

The Oppenheimer blue is a 14.62 ct Fancy Vivid Blue diamond that was initially owned by the Oppenheimer family. In 2016 it was sold for $58 million and for a while it was the most expensive diamond. 

The Okavango blue

The Okavango Blue is considered to be the largest diamond ever discovered in Botswana – its original size was 41.11 ct. This gem was presented only in 2019. It is classified as a Fancy Deep Blue stone with VVS clarity. 

However, after polishing and cutting, it turned into a 20.46 ct stone. 

Blue Diamonds vs Blue Sapphires

The impressive blue color of the Diamond reminds of the intriguing beautiful shade of Sapphires.

As Blue Diamonds display a variety of color shades – from very light blue to fancy vivid blue, so do Blue Sapphires. The color of Sapphires depends on titanium – the higher its concentration, the higher the saturation. 

And yet, despite some external similarity and association with the color of ocean water, Sapphires and Blue Diamonds are completely different stones. Sapphires can be cheaper than diamonds, give less shine – but their blue color, as a rule, will be much richer. Blue diamonds of saturated pure color will cost a cosmic amount of money, especially if we are talking about a stone of relatively big weight. However, a blue diamond is the dream of every enthusiastic collector.

If you’re interested in a blue gem, try to compare a Blue Diamond and a Blue Sapphire – see which stone inspires and pleases you more. Then ask for help from a professional gemologist – they will give you their careful recommendations and expert advice.

Subscribe to discover the world of diamonds and gems. If you have any questions, please let us know.