An Expert Guide to Natural Blue Diamonds

Blue diamonds are extremely rare and highly coveted gemstones, known for their captivating hues ranging from faint blue to fancy dark blue. These diamonds get their color from the presence of boron impurities in their carbon structure, and their value generally increases with the intensity and purity of their color. 

Blue diamonds are sourced from only a handful of mines globally. These include the Cullinan mine near Pretoria in South Africa and the Argyle mine in Australia. Historically, the renowned Golconda mine in India also produced blue diamonds.

Because of their rarity, the price of a blue diamond is very high. A 0.5-carat light blue diamond costs $26,280 on average. Deep blue and vivid blue diamonds cost much more—around $75,000 for a 0.25-carat diamond.

Here’s what we’ll cover in this article:

What is a blue diamond?
Origin of blue diamond color
What are the types of blue diamond?
What are the intensity levels of a blue diamond?
How rare is a blue diamond?
How much do blue diamonds cost?
What ring setting is the best for a blue diamond?
Popular blue diamond jewelry

Bottom Line Recommendation

We strongly recommend buying a blue diamond from a vendor who provides high-quality photos, like Leibish & Co. or James Allen. Color can vary significantly even within a specific color grade, and we want to make sure you’re getting the most for your budget. In our experience, Leibish & Co. offers the best prices and customer experience in the Fancy Color Diamond market. They also provide a high level of expertise when it comes to pairing the diamond with a jewelry setting. 

What Is a Blue Diamond?

A blue diamond is a real, natural diamond with a noticeable blue tone due to the presence of boron in the diamond’s carbon structure. Blue diamonds range in color from light blue to deep blue often with a secondary hue like violet, gray, or green. Blue diamonds are not treated or enhanced to get their color, they are found below the earth’s surface with their natural blue coloring.

Blue diamonds are found only in a few mines in the world: the Cullinan mine in South Africa, the Argyle Mine in Australia, and the Goloconda mine in India. The carat weight and intensity of blue color dictate how much a blue diamond is worth. Because of blue diamonds’ rarity, they’re usually more expensive than white diamonds and other fancy color diamonds and the large pieces are often put up for auctions. 

Origin of Blue Diamond’s Color

Blue diamonds are real, natural diamonds that form beneath the earth’s surface over billions of years. These diamonds are not color-treated or enhanced to get their blue color—it is natural. The mesmerizing color of the blue diamond comes from traces of boron in the diamond’s carbon composition.

Though often confused, sapphires are entirely different gemstones than blue diamonds. Sapphires are a member of the corundum family and contain traces of titanium, iron, magnesium, copper and chromium.

Types of Blue Diamond

Most blue diamonds are Type IIb diamonds, which account for only 0.1% of the world’s color diamonds. There’s a spectrum within blue diamonds, though. They range from light to deep, vivid blue. Most diamonds also have a secondary hue that alters their color to be more green or gray, for example.

Depending on the color intensity, blue diamonds look like pale blue gemstones, vibrant blue stones or a mix of two colors like blue and purple. Secondary hues add tint and character to the stone. No matter where a stone falls on the blue diamond color chart, it’s bound to be a stunning, rare gem.

Blue diamonds belong to the family of fancy color diamonds, the name for diamonds that exhibit a rich color. Their value is based on the diamond’s 4Cs (cut, color, clarity and carat), with color intensity being the most important factor.

Blue Diamond’s Intensity Levels

The strength of a diamond’s color is referred to as the color intensity level. Each fancy diamond has different intensity levels by which it’s evaluated. For blue diamonds, the grading scale includes Faint Blue, Very Light Blue, Light Blue, Fancy Light Blue, Fancy Blue, Fancy Intense Blue, Fancy Deep Blue and Fancy Vivid Blue. Fancy Dark is also a possibility if a secondary color is present.

Every blue diamond is considered rare, but pure colors (ie. those without a secondary modifier) are even more unique. Pure blues are hard to obtain, however, and some color combinations are quite stunning. Gray-blue and green-blue are the most common secondary colors for blue diamonds but there are many color combination possibilities. This 0.23 carat fancy light gray blue diamond from Leibish & Co. is an example of a beautiful stone with a modifying color. Even stones like these are considered exceptional.

Blue Diamond’s Rarity

Blue diamonds are rarer and more expensive than every other fancy color diamond—except for red diamonds. Blue diamonds are incredibly rare and can only be found in three areas of the world: Australia, South Africa, and India. The more intense the color of the blue diamond is, the more rare and expensive it is. Blue diamonds with a high carat weight such as 2 or 3 carat are even harder to come by, and thus extremely expensive. For instance, this 2.35 carat fancy green blue cushion cut diamond from Leibish & Co. costs $420,100. 

Some claim—based on their very high prices—that pink diamonds are more rare than blue, but that’s due to increased demand rather than reduced supply. Blue diamond’s level of rarity often makes them a target for diamond collectors, investors, and enthusiasts.

Looking for to really impress someone special? National Jeweler reports that “Sotheby’s has announced it will sell a group of eight fancy blue diamonds valued at more than $70 million total across its Magnificent Jewels auctions this year and into the spring.” The auctions will take place through spring 2023.

Blue Diamond Price

The price of a 0.3 carat light blue diamond costs $15,700 on average. The price of a 0.5 carat light blue diamond is $26,280 on average. Deep blue and vivid blue diamonds cost much more—around $75,000 for a 0.25 carat diamond. As you increase in color intensity and carat weight, blue diamond prices extend beyond $100,000, $200,000, and more. For instance, this 0.76 fancy intense blue radiant cut diamond from Leibish & Co. is priced at $410,500. A blue diamond’s value greatly increases with more intense color.

Certain color combinations like those with more gray than blue can be more affordable. For example, this 0.50 Carat Fancy Gray Blue Pear Shape Diamond from Leibish & Co. is priced at $32,100. Compare that to this 0.54 carat, Fancy Intense Blue Radiant Shape Diamond also from Leibish & Co. that’s priced at $210,775. While there is a difference in shape between the stones, the gap spans almost $180,000.

Smaller blue diamonds, like those below 0.3 Carat, are more affordable and can be used to make a special jewelry piece if paired with other stones.

Figuring out how much a blue diamond is worth is challenging because the prices range dramatically based on color and secondary hue. Because blue diamonds are so rare and unique in their specific color, it’s virtually impossible to determine a blue diamond price per carat. That’s why it’s important to assess each blue diamond to determine if it’s a good value.

If you’re in the market for a blue diamond and want to know if you’re getting a good deal, reach out to our experts for personalized advice.

Received great in-depth assistance from Veronika on my quest to buy an engagement ring for my partner. It can be quite a minefield for someone without industry know-how to get a great, well-cut diamond on the online marketplace, so the second opinion was not only welcome but desperately sought. In the end, I received wonderful advice and am confident the diamond purchased was the best my budget could afford! Thank you

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Arthur

Jan 27, 2023

Diamonds Pro helped us pick a diamond, according to our budget and a few other criteria. We ended up buying a loose diamond from James Allen. We felt that we got very good value for money. The diamond was appraised by another jeweler where we live, confirming its characteristics and value. Finally, we had the diamond set in a ring by a local jeweler, and we’re very pleased with the result! Thank you Diamonds Pro 😊

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Mikeela Teaquila

Dec 26, 2022

An Affordable Alternative to Ultra Rare Fancy Color Diamonds

While fancy blue diamonds may be out of the price range for most people, you may want to consider a lab-created fancy color diamond if you want to find an affordable gift.

Check out what Blue Nile has to offer here. And don’t forget to look at James Allen’s inventory as well.

Blue Diamond Engagement Ring Settings

There are a variety of engagement ring settings that help make a blue diamond stand out. The best settings for blue diamonds are outlined below.

Style 1: Halo setting

Enhance the beauty of your blue diamond by surrounding it with other diamonds. Add side stones to increase your ring’s carat weight.

Halo setting example: Fancy Gray Blue Pear Diamond Dress Ring from Leibish & Co.

Style 2: Tension setting

Place your blue diamond in center stage with a tension setting. Isolating the starkly colored diamond can help to make its color pop.

Prong setting example: Tension set Vivid Fancy Deep Blue Emerald Cut Diamond from Leibish & Co.

Style 3: Three-stone setting

Flank either side of your blue diamond with small colorless diamonds. You’ll increase the brilliance of your ring without taking away from the blue diamond’s color.

Three-stone setting example: Fancy Gray-Blue and White Diamond Three Stone Ring from Leibish & Co.. The geometric pattern created by the two trillion side stones brings out the exceptional color of the center stone.

Popular Jewelry Settings for Blue Diamond

Besides an engagement ring, you can place a blue diamond in a pendant or a pair of earrings.

Build a piece of jewelry that has meaning and significant value. Choose a pendant necklace or set of earrings to match the personal style of the wearer.

Blue diamond stud earrings inspiration: Fancy Gray Blue Round Brilliant Earring Studs from Leibish & Co.

Blue diamond ornate earrings inspiration: Fancy Intense Blue Diamond Flower Earrings from Leibish & Co.

Blue diamond pendant inspiration: Round Sapphire & Diamond Drop Pendant from Leibish & Co. (Note: this is a sapphire, not a blue diamond)

Find the best looking blue diamond for your budgeting by selecting from the Leibish & Co. or James Allen collections. If you have questions about purchasing a blue diamond, contact our diamond experts.

Leibish & Co Leibish & Co is the industry leader in the world of Fancy Color Diamonds. Their inventory size and prices are the best in the business, and their expertise in this highly specialized field will ensure that your diamond is set in a way to maximize its color.

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What we love about them:

• Largest and best inventory of fancy color diamonds
• Best prices for fancy color diamonds
• Industry leading expertise will ensure the color of your diamond is maximized in its setting
• Leading bidders in the annual Argyle auction
• Highest quality jewelry available online
• Free shipping
• Free resizing within first 2 years of purchase
• Items comes with professional appraisal for insurance
• 30 day no questions asked free return policy

About the author

Mike Fried Mike Fried has over 25 years experience in the diamond industry working with Leo Schachter Diamonds, Moshe Namdar Diamonds, and joining The Diamond Pro in 2007. He is recognized as an industry expert and has been quoted in publications such as Us, People, Page Six, The Next Web and more.