How to Buy Blue Diamonds – Everything you Need to Know

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It is imperative that you buy your diamonds from a reputable dealer that offers high-quality photos and GIA certification. We recommend James Allen and Blue Nile for their selection and excellent customer service. 

Diamonds are a natural miracle, being unbelievably beautiful and one of the strongest materials on earth. Diamonds are rare, precious, enchanting, and the most coveted gemstone.

Can you think of something that is spectacular because of its minor imperfections? Colored diamonds! But how?

The answer lies in the fascinating world of mineralogy. 

Natural diamonds are a mineral and a rare, solid form of crystalline carbon. Most diamonds gather defects during their growth cycle. A few of these defects or imperfections modify how light passes through the stone, creating a color effect on the observer. These slight imperfections hiding inside colored diamonds are what make them spectacular. 

Watch to see The Oppenheimer Blue Diamond:

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About Blue Diamonds

The blue sky meeting the blue sea makes the perfect union in this world.
The thought of the color blue brings a sense of peace and calmness for the mind and body.

A blue diamond has a noticeable blue tone with colors ranging from light blue to deep blue. In addition, the blue diamond is often accompanied by secondary hues such as violet, gray, or green.

The blue color of the blue diamond is due to the presence of boron in the diamond's carbon structure. When a few boron molecules substitute for carbon molecules in the diamond's structure, it produces a blue color. This imperfection or defect changes the way light passes through the diamond crystal and results in a blue color, the more boron that substitutes for carbon, the stronger the blue color of the diamond.

Blue diamonds belong to the family of Fancy Color Diamonds, the name for diamonds that exhibit a rich color.  

The Rarity of the Blue Diamond

Natural blue-colored diamonds are extremely rare. Their rare color and high clarity make them exceptionally valuable gems. Blue diamonds are rarer and more expensive than every other fancy color diamonds—except for red diamonds. It is estimated that blue diamonds account for only 0.1% of the world's total colored diamonds.    

Very few mines produce blue diamonds – the Cullinan mine in South Africa, the Argyle mine in Western Australia, the Golkonda mine in India, and the Lesteng mine in South Africa.

Since blue diamonds are rare to such an extent, they are coveted by diamond collectors, connoisseurs, and investors. 

***Did you know that 'The Hope Diamond' is the world's most famous blue diamond? It weighs 45.52 carats and has a fancy dark grayish blue color. It is on display at the National Museum of Natural History in Washington.

Watch to see the world's most valuable blue diamond:

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Blue Diamond Pricing

 A blue diamond's value is based on its 4Cs (Cut, Color, Clarity, and Carat), with Color intensity being the most crucial factor.

Blue diamond prices can vary greatly depending upon the intensity of their color and hue. The most valuable natural blue diamonds are those with a purely blue color uniformly distributed through the gem. In general terms, the more intense the blue color, the more precious it will be, and the higher its price will be.

Blue diamonds are extremely rare, and their prices can exceed a million dollars per carat.

  • Blue diamonds with higher carat weight, such as 2 and 3 carats, are challenging to find, and therefore are unbelievably expensive.
  •  A 0.3 carat light blue diamond costs about $15,700 and 0.5 carat light blue diamond cost around $26,280.
  • Deep blue and vivid blue diamonds are much more expensive and cost around $75,000 for a 0.25-carat diamond.
  • Smaller diamonds with a carat weight less than 0.3 carats are more affordable and can be used to make jewelry by pairing it with white diamonds or other stones.    

The prices can even rise higher exorbitantly as the blue diamond increases in color intensity and carat weight.

Evaluating the worth of a blue diamond is one of the most challenging tasks as prices change drastically based on shade and secondary hue. Hence, assessing each blue diamond individually is essential to determine its worth rather than following one formula for all.

Blue Diamonds on James Allens Website

Blue Diamonds on James Allens Website

The 4C's of Blue Diamonds

  • Color: Prices go up with the color intensity of blue diamonds. Deep blue and vivid blue diamonds are very expensive.
  • Carat: Price per carat is affected in two ways. One by the color – the more intense the color, the higher is the price per carat. Secondly, by weight – the larger the blue diamond, the higher the price per carat. 
  • Clarity: Clarity does not play an essential role in fancy colored diamonds as it does in white diamonds. Color and intensity are far more critical factors than clarity.
  • Cut: For the colored diamonds, it is vital to settle for a cut that fully brings out the diamond's color while balancing the best sparkle at the same time.


Since blue diamonds are valued by their color, we need to learn about the different aspects of color - tone, hue, and saturation. The GIA considers all three factors of color and then sums them up into one grading system.

The tone is how dark or light the stone is. This characteristic doesn't have as much importance as hue or saturation because if the stone is too light or dark, you won't see the color anyway. 

Hue is the visible color a stone exhibits. In the case of blue diamonds, the primary hue is blue. Secondary colors can be present as well, with the most common being green, violet, and gray. The most valuable blue diamonds either have secondary hues that do not divert from the stone's primary color or do not have secondary hues at all.

Secondary Hue: The presence of a secondary hue significantly impacts the blue diamond's price. Greens, greys, or, more rarely, purple secondary hues may be present. While neither is desirable, gems with greenish hues hold more value than those with a slight purple color. 

Saturation refers to how intense the color is. Stones with faint or light blues are less valuable than stones with deep and vivid blues.

The strength of a diamond's color is known as the color intensity level. Each Fancy diamond has different intensity levels by which it is 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
  • Fancy Vivid Blue
  • Fancy Dark (if a secondary color is present)

Secondary color possibilities create a myriad of color combinations. In the case of fancy blue diamonds, some of the options may include the following secondary colors:

  • Gray
  • Grayish
  • Green
  • Greenish
  • Violetish
  • Gray Greenish
  • Grayish Greenish


The most crucial and alluring feature of the blue diamond is its fascinating blue color. Cuts that maximize brilliance are less desirable, as the more brilliance, the less you see color; this includes round and princess cuts. Fancy shapes tend to balance ultimate color saturation with maximum sparkle, and therefore fancy shapes are preferred for blue diamonds.

The most popular shapes for blue diamonds are radiant and cushion cuts, as they let the blue diamond disperse its color in the best possible manner. Some other shapes that work well are pear, emerald, and round. The least common shapes are marquise and oval.


Blue diamonds are graded for clarity in the same way colorless diamonds are. The fewer the internal imperfections(inclusions), the higher the value of the stone.

Look for stones that are eye-clean (do not have flaws visible with the naked eye). You can often find eye-clean stones among blue diamonds graded as low as SI1-SI2.

Carat Weight

The higher the carat weight of the blue diamond, the more price per carat it becomes.

Settings for Blue Diamonds

Appropriate ring settings can create a significant impact by making the blue diamond stand out and shine. Some of the best settings for blue diamonds are : 

  • Halo Setting: Blue diamonds surrounded by other diamonds enhance their beauty. Adding side stones can help in adding to the ring's carat weight.
  • Tension Setting: In a tension setting, the band's tension secures the diamond in place, which creates an appearance of the diamond in mid-air. Tension settings can help the blue color of the diamond pop.
  • Three-stone Setting: By adding smaller white diamonds on the sides of a blue diamond, its brilliance can be enhanced. 

Blue Diamonds for Engagement Rings

The color blue is symbolic of loyalty and trust, and therefore a blue diamond is a beautiful and meaningful addition to an engagement ring. Also, blue diamonds are durable and scratch-resistant, making them ideal for daily wear.

If a Blue Diamond is Beyond Your Budget

Since blue diamonds are extremely expensive and rare, the budget is the biggest hurdle in buying them. However, if you have your heart and eyes set on a blue diamond and think it is out of the budget, there are other more affordable options. 

Lab-created Diamonds:  Lab-created stones are grown or created inside a laboratory. These lab-grown stones are similar to natural stones in all aspects except that they are grown in a lab.

A lab-created blue diamond would still be expensive but much cheaper than its natural counterpart (they can be 20% to 50% less expensive).

Treated or Enhanced Stones: Enhanced blue diamonds are natural diamonds that have undergone color enhancement treatments. Such methods, usually irradiation, transform the otherwise colorless precious stone into a vibrant shade of blue. These treatments are typically permanent and do not damage the diamond's chemical structure.

The enhanced blue diamond is relatively affordable and a brilliant alternative to the natural blue diamond.

Blue Sapphire Halo Engagement Ring Halo from Evorden on Etsy

A Beautiful Blue Sapphire Diamond Halo Engagement Ring Halo from Evorden on Etsy

Blue Sapphires: If you are on a tight budget, a blue sapphire can be an ideal alternative. Blue sapphires are quite durable (rated 9 out of 10 on Mohs scale of hardness) and come in various shades with impressive sparkle.

How to Buy a Blue Diamond

Here are the steps to buying a blue diamond:

  1. Start with budget - diamond pricing varies so much that you will want a budget in place before you start. 
  2. Decide what cuts and shapes you prefer. 
  3. What carat size are you wanting? Anything below 1 carat will be most affordable. 
  4. Go to James Allen or Blue Nile and browse colored diamonds to estimate cost and sizes. 
  5. Decide on a cut or shape and carat size.
  6. Be sure to purchase from a seller that includes GIA certification. 

Where to Purchase Blue Diamonds?

James Allen

It is highly recommended to buy diamonds from reputed sellers who provide GIA certificates with diamonds. One of the most trusted and reputed diamond sellers is James Allen.

James Allen has revolutionized the way people buy engagement rings and diamond jewelry. They are considered to be one of the premier diamond engagement ring retailers in the world. With 18+ years of experience, they are the leader in online diamond sales. You can be sure to buy the best diamond at the best price at James Allen.

Click here to visit James Allen and become a proud owner of this never-fading star!

Blue Nile

Another excellent online seller is Blue Nile. Blue Nile provides customers with exceptional diamond buying tips and unbiased diamond and jewelry education guides. In addition, diamond and jewelry experts are available 24/7 to answer all questions.

Blue Nile stands behind its products with industry-leading Diamond Certification, secure delivery, 30-day returns, and lifetime guarantees.

Visit Blue Nile today!

Share the Knowledge

6 thoughts on “How to Buy Blue Diamonds – Everything you Need to Know”

  1. Nice facts about diamonds and how and why the color of diamonds appear as they do. I have been searching for diamond products for my wife both for our wedding, she got quite a big one :). After that, at each wedding day celebration, I have been searching for the possibility to buy an additional diamond product for her. The one she has now is on her wedding ring. 

    I didn´t ´realize that it was boron that causes the blue color of blue diamonds. I thought it was how the light was bent through the diamond. But, a question about boron, isn´t boron a very toxic matter, and as such would harm you if you use the diamond as jewelry?

    I think I need to save up some more money to buy my wife a blue diamond for our next wedding day. It would be a perfect match for her brown eyes and dark complection.

    • The boron is trapped in the diamond, so I don’t think it is harmful. That sounds like a wonderful gift for your wife!

  2. Wow, I learned so much new reading your article. I had no idea that diamonds could be grown in a laboratory and I dint know they are the rarest ones. I love the idea and the meaning of having them in a wedding ring but I am not to doubt we could possibly effort a blue diamond ring. 

    Thanks for giving some more affordable alternatives too.

    Are diamonds pretty consistent in their value or do prices change a lot over the years?

    How long does it take to grow a diamond in a laboratory and how long will it take to grow a diamond the natural way?

    Thanks for teaching us such interesting facts about vintage jewellery, I definitely gained knowledge on the topic and will look at diamonds differently next time when I see one in the shop.

    Best wishes.


    • Hi Jude, thanks for the questions 🙂

      Diamond prices have increased approximately 32 – 33% over the last 10 years, meaning they gained an average of 4% every year.

      It takes 7-10 days to grow a 1 carat lab diamond, and about a month to grow a 3 carat diamond. A natural diamond takes between 1 billion and 3.3 billion years!

  3. Most of us would like to have this beauty but I wonder how many of us really wonder to find out how they are being formed. This was a good read as I have actually learnt something about diamonds that I did not know about before. From your post it sure seems the more scarce these diamonds are the more expensive they would be which would make people want them even more. But they sure are expensive and are meant for the affluent. Buying a diamond for over a million dollars. That’s a lot of money.

  4. Hello awesome article you have here Nice facts about diamonds and how and why the color of diamonds appear as they do. I have been searching for diamond products for my wife both for our wedding, she got quite a big one :). After that, at each wedding day celebration, I have been searching for the possibility to buy an additional diamond product for her. The one she has now is on her wedding ring.


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