Natural Blue Diamond Guide: From Science to Jewelry Settings

Last Updated on September 27, 2023 by Juli "Jewels" Church

Ever held a piece of the sky in your hands?

I can tell you that's the sensation natural blue diamonds evoke in me. Each one a rarity, a geological marvel, an enigma waiting to be unraveled. 

okavango blue diamond

In this guide, I'll guide you through the answers to the questions you didn't even know you had: Is a blue diamond what you want as an engagement ring center stone? How do you sidestep pitfalls to unearth a true treasure? What alarms should ring in your head when something seems off?

Prepare to unearth the secrets; we're diving deep into the multi-faceted world of blue diamonds.

What Are Blue Diamonds?

Fancy colored diamonds are diamonds that have been introduced to different impurities while forming in the earth. For a blue diamond to form, the diamond crystal must have boron impurities.  

Blue diamonds are a rare color of diamond. The likelihood of boron being introduced to the crystal and that it would be properly saturated is rare. Some blue diamonds may either have a blue green tint or a grayish tint. 

blue diamonds at James Allen

The most famous blue diamond in the world is the Hope Diamond. It's said to be a cursed diamond as bad luck has befallen many of the owners throughout history. The Hope Diamond is currently available to see at the Smithsonian Museum in Washington DC.

Check out the video below if you'd like to learn the history behind this accursed blue diamond. 

Natural, untreated blue diamonds are very rare. You can still have a natural blue diamond that has been subjected to heat treatment in order to intensify color. Lab-grown blue diamonds are still pretty expensive, but much cheaper and have better color and clarity. 

You should identify if a blue diamond has had treatment by its grading report. 

Natural Blue Diamonds vs Treated: What's the Difference?

When you're considering the purchase of a blue diamond, one of the critical decisions you'll face is whether to go for a natural or treated gem. Understanding the differences between these two categories can greatly influence not only the price but also the overall value and significance of your diamond. Let's delve into the key distinctions:

Origin and Formation

Natural blue diamonds are geological marvels, formed over billions of years under extreme heat and pressure. The presence of boron during their formation, as previously mentioned, lends them their iconic blue hue. These diamonds are among the rarest, constituting a minuscule fraction of worldwide diamond production.

Treated blue diamonds are natural diamonds that have undergone specific processes to either induce or enhance their blue color. Treatments like High-Temperature Annealing or laser drilling are commonly used and are usually permanent.

Color Uniformity and Intensity

Natural blue diamonds often display a more nuanced and complex color profile, potentially featuring different shades and hues depending on the viewing angle. Treated blue diamonds usually exhibit a more uniform color, which, while beautiful, lacks the complexity that can be found in a natural stone.

Inclusions and Purity

Natural blue diamonds are formed over billions of years, which means they may have unique inclusions—sometimes referred to as the diamond's "fingerprints." Treated diamonds, especially those that have undergone laser drilling to remove inclusions, may lack these natural characteristics.

Resale Value

Natural blue diamonds are more likely to retain or increase in value over time. Their rarity and the increasing demand often make them a more stable investment. Treated blue diamonds typically depreciate faster and are less likely to increase in value.

Ethical Considerations

Natural blue diamonds are usually extracted through mining, which brings into play ethical concerns about labor practices and environmental impact. Treated diamonds could be considered more ethical if the original diamond is sourced responsibly, but this varies from vendor to vendor.

What to Look for When Buying Blue Diamonds: The 4Cs

You've probably heard of the 4Cs by now, a diamond grading system put forth by the Gemological Institute of America. With gemstones, they follow the same basic guidelines, but without the actual grades. 


In white or colorless diamonds, cut serves as the foundation of the stone and what will ultimately reflect brilliance and sparkle. The most desirable cut grades are ideal or excellent. But with colored diamonds, you don't need to reflect too much brilliance.

Brilliant cut diamonds like round, princess, and cushion cuts are not recommended diamond cuts for blue diamonds. Too much brilliance draws away from the color.

Read also: The complete cushion cut guide

Officially, shapes other than round don't have cut grades. Round diamonds can be excellent and ideal cuts. Many times, companies will separate their fancy shapes into Good and Very Good grades. But the best way to pick out a non-round diamond shape is to look at proportions and measurements required for that particular shape. Each one is different. 

James Allen blue diamonds


Blue Diamonds are most valued by their color and their color tone, hue, and saturation. But instead of grading them individually, the GIA takes into account all three factors and sums them up into one grading system.

Tone is basically how dark or light the stone is. Tone doesn't have as much weight as hue or saturation, given that if a blue diamond is too light or too dark, the hue would be difficult to discern anyway. 

The grading terms for fancy diamonds can be found as follows: Faint, Very Light, Light, Fancy Light, Fancy, Fancy Dark, Fancy Deep, Fancy Intense, or Fancy Vivid. Most natural blue diamonds found are a Fancy Light or better.

gem tone scale

Hue is the color that can be seen through the light in a gemstone. The GIA hue scale is red, orange, yellow, green, blue, violet, and purple. Sapphires can be green with secondary hues of either violet or green. 

Most of the time, you'll want a fancy colored diamond with one solid hue. Often times, colored gemstones exude hues of another color, referred to as secondary hues.

Some secondary hues can make a fancy diamond more valuable, though most do not. Purplish blue or yellowish green hues are undesirable, but there are a couple exceptions. Fancy brown diamonds are an exception, and so are fancy dark blue diamonds and grayish blue diamonds. 

Steve Evans from Citizen of the World - Americana: The Hope Diamond, CC BY 2.0,  

The saturation of a blue diamond is important in discerning its overall quality. The saturation covers the intensity of the hue. A Fancy Blue diamond won't have the same look as a fancy yellow diamond, because the saturation is high on fancy yellow diamonds. A Fancy Intense blue diamond is going to be closer to a Fancy Yellow diamond. 


Because a natural fancy blue diamond is rare in itself, it's even more rare to find one that is eye-clean, or free of inclusions to the naked eye. It's normal for a blue diamond to have small inclusions, even if it does lower it's value. Small inclusions should have a miniscule impact on clarity grading. 

Read also: What are the different types of inclusions?

Fancy colored diamonds are divided into types, similar to color gemstones. But while colored stones have Type I, II, and III classifications, it's a bit different with colored diamonds. They are divided in Type Ia, Type IIa, Type Ib and Type IIb. 

Type Ia colored diamonds contain nitrogen aggregates throughout the crystal structure. This creates a yellowish color, which makes fancy yellow and orange diamonds a Type Ia colored diamond. 

Type IIa colored diamonds have a different fluorescence and no visible absorption. They won't have any nitrogen impurities eithers. Type IIa fancy diamonds are considered the most rare. Blue diamonds fall under this category. Only 1% of diamonds mined is a Type IIa, which gives you an idea on how rare they are and why the cost is so expensive.


You already know that untreated natural blue diamonds are very rare and pricey. Check out this .22 carat fancy intense blue diamond from Leibish and Co. The price of it is over $60,000! 

fancy intense blue diamond

The stone is gorgeous, no doubt. Most of us aren't going to be able to pay the cost of it. Even more than that, a .21 carat diamond really doesn't do a whole lot in jewelry either, except as an accent stone. 

If you do want a blue diamond in a larger carat weight, but don't want to pay that much, you do have a couple options. You can always look into treated blue diamonds, which have been enhanced by heat.

You can also look into synthetic or lab-created blue diamonds as well, which can cut cost on blue diamonds too.

Recommended Blue Diamond Jewelry Settings

When it comes to showcasing a blue diamond, the setting is a pivotal yet often overlooked element that can accentuate or diminish the stone's intrinsic beauty. And trust me, as a diamontologist, I've seen the remarkable difference the right setting can make. Whether you're considering a ring, earrings, or even a brooch, here are my top recommendations to help you make an informed decision.

Ring Settings

Solitaire Setting: A timeless choice that places the blue diamond front and center. Ideal metals: platinum or white gold for a lustrous complement to the blue.

glamira blue diamond solitaire

Blue diamond solitaire ring by Glamira

Halo Setting: A circle of smaller diamonds accentuates the central blue gem, adding layers of brilliance. Ideal metals: rose gold to create a subtle, romantic contrast.

Round fancy blue gray double halo diamond engagement ring from Leibish & Co.

Round fancy blue gray double halo diamond engagement ring from Leibish & Co.

Pave Setting: An opulent option with diamonds lining the band, making the center diamond appear even grander. Ideal metals: white gold or platinum to maintain a unified, icy sparkle.

Blue Princess Cut Diamond Engagement Ring

Blue princess cut diamond pave ring via FrontJewelers

natural blue diamond pentagon ring

Blue pentagon diamond pave ring

Bezel Setting: Encases the diamond in a metal rim for a modern, secure setting. Ideal metals: white or silver-tone metals to contrast the blue hue dramatically.

glamira blue diamond bezel pave

Bezel set blue diamond ring via Glamira

Vintage Setting: Embraces the beauty of intricate details and antique charm. Ideal metals: yellow gold to bring a warm, classic feel to the cold blue.

vintage blue diamond ring

Vintage blue diamond ring via Eragem

Pendant Settings

Prong Setting: Maximizes light exposure, ideal for solitaire pendants. Ideal metals: white gold or platinum for an elegant touch.

glamira blue diamond pendant in prong setting

via Glamira

Bezel Setting: Offers a sleek, contemporary look suitable for modern attire. Ideal metals: rose gold for a unique contrast.


blue diamond stud earrings

Blue diamond bezel stud earrings

Stud Setting: A minimalist design that's perfect for daily wear. Ideal metals: white gold or platinum to enhance the blue.

Drop Setting: Incorporates movement and additional elements for a dynamic look. Ideal metals: yellow gold for a rich contrast.


Tennis Bracelet Setting: Features a line of diamonds for a sophisticated sparkle. Ideal metals: platinum for durability and elegance.

blue diamond bracelet

Blue diamond bracelet via Eragem

Bangle Setting: Offers a more geometric, modern aesthetic. Ideal metals: white gold or silver for a chic, industrial feel.

Where to Buy Natural Blue Diamonds 

#1 Blue Nile

Buying blue diamonds at Blue Nile
available blue diamonds at Blue Nile

Blue Nile is frequently at the top of our guides alongside James Allen, but today it takes the top spot. Out of all of our recommended retailers today, Blue Nile has the widest selection of natural diamonds. 

They carry about 25 loose blue diamonds, but around half of them are .5 carat minimum. All of the diamonds (colored or otherwise) at Blue Nile are GIA certified, which is essential to buying diamonds. They are also untreated, which makes the prices pretty high. 

The minimum cost of a blue diamond at Blue Nile is going to run you around $57,000 for a .27 carat marquise blue diamond. While this is highly expensive, keep in mind how rare blue diamonds are to begin with. The high end runs around $370,000. 

Blue Nile also has a section for colored lab diamond jewelry, including blue diamonds. Under the Lightbox Jewelry section, you have around 20 different options for lab-created blue diamond necklaces, earrings, bracelets and rings. They are considerably less expensive than the natural blue diamonds. 

My biggest issue with buying blue diamonds from Blue Nile is that they don't offer a warranty for your ring setting. They have a manufacturer's warranty, but that only covers design flaws.

For routine maintenance like rhodium plating white gold, you'll have to pay out of pocket. You do get one free ring sizing though. 

If you don't like your blue diamond from Blue Nile, they offer a 30 day return policy. They have 24/7 customer service available for convenience and a long standing positive reputation as the first online diamond retailer. 

Blue Nile Lab grown blue and white diamonds


  • Natural untreated blue diamonds
  • Lab grown blue diamonds
  • Lifetime upgrade
  • Clear 360˚ view


  • Manufacturer's warranty

#3. James Allen

buying blue diamonds at James Allen

It's kinda surprising to see James Allen at the bottom of the list today as they normally top many of our guides. 

James Allen has their own section of loose diamonds marked for fancy color diamonds. They also offer a section of lab created fancy colored diamonds, but only carry yellow diamonds at this time.

The main reason why they're so low on the blue diamond list is because they have a very small collection. There are currently less than 10 natural blue diamonds. Half of them are over 1/2 carat. 

They have a section for natural, blue diamonds, but currently carry under 10 loose blue diamonds. The low end of cost starts around $7,300 and goes up to $400,000. These blue diamonds are untreated and come with a grading report from the GIA

James Allen automatically sets the criteria for tone on their blue diamonds to be Fancy, Fancy Intense, or Fancy Vivid in their search. Under these tones, there are only 4 available options. 

If you happen to purchase a gorgeous blue diamond from James Allen that costs $30,000 or more, they offer you a free ring setting valued up to $1,500 or $1,500 off on a more expensive setting you might've chosen. James Allen appreciates their customers dropping a pretty penny on their diamonds, so they want to give back a little. 

Lastly, they've got a free lifetime warranty. The warranty covers routine maintenance on diamond jewelry which includes rhodium plating white gold, tightening stones, and jewelry steam cleaning.

You do have to pay a $35 shipping fee to send it out. You can even send it off to some select Jared repair shops. They also give one free ring resizing for all engagement and wedding rings. 

grayish blue diamond at James Allen


  • GIA certified
  • Lifetime warranty
  • Clear 360˚ view


  • small selection
  • most over $15,000

#4 Leibish & Co.

leibish blue diamond screenshot

I was thoroughly impressed with Leibish & Co.'s collection. They offer a wide variety of these unique gems, with a broad spectrum of hues, clarities, and cuts, all certified by reputable gemological labs. What sets Leibish & Co. apart is their specialized expertise in fancy colored diamonds. The staff is knowledgeable and passionate, always eager to answer questions and provide guidance.

leibish fancy vivid blue diamond 0.46 ct VS2 emerald cut

Navigating their website was a breeze, allowing me to easily refine my search based on specific preferences. One point worth noting is that the settings for these natural blue diamonds can be pricier compared to other online vendors. However, the quality and expertise you receive justify the investment.

The craftsmanship of the jewelry is top-notch, each piece expertly designed to highlight the natural beauty of the blue diamond. The company's customer service is also exceptional. From the moment I placed my order, I received regular updates and found the shipping process to be both fast and secure.

Overall, if you're in the market for a natural blue diamond, Leibish & Co. comes highly recommended for their quality, selection, and customer service. They're a reliable choice for anyone seeking a truly unique and high-quality piece of jewelry.


  • Wide selection of high-quality, certified natural blue diamonds
  • Expertise in fancy colored diamonds with knowledgeable staff
  • Beautiful and unique pieces 
  • Excellent customer service with fast and secure shipping
  • User-friendly website


  • High prices
  • Settings can be pricier than other online vendors
  • No buyback program

#4 Brilliant Earth

Blue diamonds at Brilliant Earth

Brilliant Earth is a name that comes up frequently in online diamonds. Most people know them because of their popular "Beyond Conflict Free" campaign. While they do follow the Kimberley Process like all of our recommended retailers, Brilliant Earth can trace the origin of their diamonds. Other online stores don't know exactly where they come from. 

They are not known for their fancy color diamonds but they do carry them. I bring up Brilliant Earth in this roundup as an option for those who are considering lab-created fancy blue diamonds.

I think they have the best range of blue shades out of all of our retailers. You can go for a midnight blue sapphire, or an icy blue sapphire. Their 360˚ video is controllable and they make it easy to see every aspect of your diamond. 

Brilliant Earth also has a lifetime manufacturing warranty, should your blue diamond ring have any defects in the craftsmanship. They do take a $50 fee from you to assess if it is a defect. If so, they'll refund that $50 back to you. Otherwise, it'll go toward a repair or they'll keep it to cover shipping costs. So make sure you know it's a flaw if you don't have the money for a repair. 

For routine maintenance like retipping prongs and tightening stones, they offer a Extended Service Plan, which is a warranty you pay for. This will cover routine maintenance for 3 years and is based on a sliding scale. 

Check out this lab created fancy vivid blue diamond from Brilliant Earth below:

lab created fancy vivid blue diamond from Brilliant Earth


  • Wide range of blue diamonds
  • Option for purchasable warranty
  • Lifetime upgrade
  • Clear and controllable 360˚ view


  • Only 3 year maintenance plan you have to pay for
  • No natural diamonds currently

How to Get the Best Deal When Buying Blue Diamonds Online

Buying a blue diamond online can be a oh-so-exciting, but it requires a certain soberness, careful consideration and research. Getting the best deal involves more than just looking for the lowest price. Here are some tips to help you secure the best value for your investment:

Research and Compare Sellers

The internet is rife with diamond sellers, but not all are created equal. Look for online vendors who are reputable, certified, and have positive customer reviews. Compare their offerings, return policies, and customer service features.

Ask for Certification

Always request a certificate from a reputable gemological lab. This will provide crucial information about the diamond's quality, origin, and any treatments it may have undergone. Certification offers you a standard measure for comparing prices among different sellers.

Understand the Four Cs

Familiarize yourself with the Four Cs that we've discussed in the previous section. Cut, Clarity, Color, and Carat—each of these factors can significantly influence the price.

Get the Grading Report

If you are going to spend the cash to buy a natural, untreated blue diamond online, you'll want to make sure you're not being duped. I'd love to say everything is fair and true in the online jewelry market, but it simply isn't. By getting a grading report from a reputable laboratory like GIA or the AGS.

The GIA has grading reports for natural and lab colored diamonds. There are two types of reports for natural diamond: the standard colored diamond grading report and the color grading and origin report. The origin report tells you where the diamond comes from and is also laser-inscribed. 

colored diamond gia report

Leverage Online Tools and Filters

Most online stores offer tools to help you narrow down your choices based on your preferences and budget. Use these filters wisely to navigate through the plethora of options and pinpoint exactly what you're looking for.

Consider the Setting

Remember, the setting can be as impactful as the diamond itself, both aesthetically and financially. Some settings might be more expensive, especially for rare gems like natural blue diamonds. Factor this into your overall budget.

Take Advantage of Sales and Promotions

Keep an eye out for promotional events, discounts, or seasonal sales. The retailers I've mentioned in this post offer such opportunities, especially around holidays or milestone events.

Know the Treatments

The enhancement of diamonds to produce or intensify color involves a variety of techniques. These treatments do generally lower the diamond's value compared to natural, untreated counterparts, but they make these eye-catching gems more accessible to consumers.

If you decide to go with a treated synthetic or mined blue diamond, make sure you know what sort of treatments your stone has been subjected to. If it has been irradiated with heat to obtain or enhance its blue color, you shouldn't have to worry about it fading.

Only when exposed to high temps of 500 degrees Celsius should you see a blue diamond lose its blue color. However, it's important to let any jeweler that might be working on your treated blue diamond ring setting of its treatments. The jeweler's torch could alter the color, so they'll just have to remove the stone before working on its metalwork. 

Here are some common methods used to treat diamonds for achieving a blue hue:

High-Temperature Annealing

In this process, diamonds are subjected to high temperatures and sometimes pressure to change or enhance their color. While it's a permanent treatment, the resultant diamond usually has a lower market value because the color is artificially induced.

Irradiation Followed by Annealing

This two-step process first involves bombarding the diamond with fast electrons or neutrons (irradiation) to change its atomic structure and hence its color. The diamond is then annealed to stabilize the new color. This produces a range of colors, including blue.


Less commonly, a thin layer of a specific material may be applied to the diamond's surface to alter its appearance. This method is generally less stable and can wear off or be scratched easily, significantly lowering the diamond's value.

Laser Drilling and Filling

While not directly aimed at changing the diamond's color, this process is used to remove inclusions. By doing so, the diamond may appear more transparent, which can alter its apparent color. Because this treatment impacts the stone's natural state, it typically decreases its value.

HPHT (High Pressure, High Temperature)

This method is similar to the natural conditions under which diamonds form. While it is often used to improve clarity, it can also alter color. HPHT treatment can be detected only by professional testing and does decrease the gem's value.

Impact on Value

Treated diamonds are less valuable than their natural counterparts because they are more common and lack the "natural" tag, which is often a crucial selling point. Additionally, some treatments like coatings are impermanent, making the diamond even less valuable. Nevertheless, they offer a budget-friendly entry point into the world of colored diamonds, provided you're aware of the trade-offs involved.

Again, when considering a treated diamond, always consult a reputable jeweler and ask for a certificate that states any treatments the diamond has undergone. This ensures transparency and helps you make an informed decision.

Red Flags When Buying Blue Diamonds Online

While the online space provides an abundance of options, it also presents potential pitfalls. Here are some red flags to be aware of:

  • Absence of Certification: No certificate from a reputable gemological lab can signal issues with authenticity and quality.
  • Vague or Incomplete Descriptions: Lack of details about the Four Cs—Cut, Clarity, Color, Carat—may mask lower quality or deceptive practices.
  • No Return or Exchange Policy: A missing or unclear return policy often indicates a lack of confidence in the product or an attempt to sell subpar goods.
  • Extremely Low Prices: Prices that seem too good to be true usually are, often signaling poor quality or undisclosed treatments. Any natural and untreated blue diamonds should always be expensive. There is no such thing as a great deal on a blue diamond. 
  • No Customer Reviews or Excessive Negative Reviews: An absence or plethora of negative reviews, especially concerning product quality or customer service, is concerning.
  • High-Pressure Sales Tactics: Pressure to make a quick decision, due to supposed high demand or a soon-ending promotion, is a red flag.
  • Poor Website Design or Functionality: A subpar or confusing website often indicates a less reputable seller.
  • Lack of Contact Information: Missing verifiable contact details makes it difficult to resolve issues or verify the seller's legitimacy.
  • Discrepancies in Photos and Descriptions: Inconsistencies between product images and listed details should raise suspicions.

Blue Diamond FAQs

Are Blue Diamonds Good for an Engagement Ring?

Blue diamonds make exceptional engagement rings for several reasons. First, their rarity adds a unique and special touch to the occasion, setting the ring apart from more traditional options. Second, the rich blue hue symbolizes depth, stability, and loyalty—apt sentiments for a lifelong commitment.

Moreover, blue diamonds are certified for quality and durability, making them a long-lasting choice. However, they can be pricier due to their rarity, so budget considerations are essential. 

Are Blue Diamonds More Expensive?

A natural blue diamond that doesn't have any treatments is very rare. In fact, all fancy colored diamonds tend to be way more expensive than colorless natural diamonds. Even the smallest of natural untreated blue diamonds can cost tens of thousands of dollars. 

Natural blue diamonds are among the rarest of fancy colored diamonds, so they are some of the most expensive diamonds you'll find out on the market. Pink diamonds and lab-created yellow diamonds are less expensive. Red diamonds are the most expensive.

Is it safe to buy blue diamonds online?

Purchasing from a reputable, certified online vendor can be as secure as buying from a brick-and-mortar store. Ensure that the vendor has a secure payment gateway and a solid return policy.

What should I look for in a setting for a blue diamond?

The setting should not only complement the diamond aesthetically but also secure it firmly. Some settings may be pricier, particularly for rarer stones like natural blue diamonds.

What should I do once the diamond arrives?

Upon receiving your diamond, it's advisable to get it appraised by an independent gemologist to ensure it matches its certification and your expectations.

A Piece of Earth and Sky

Whether you're considering this purchase for an engagement ring, a stunning pair of earrings, or a keepsake anklet, remember: you're not just buying a stone. You're investing in a rare piece of Earth's beauty, a fragment of cosmic history, and a testament to human craftsmanship. Take your time, ask the right questions, and let your intuition guide you alongside the facts.

Your perfect blue diamond is out there, waiting to resonate with you. Happy hunting!

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