Top 3 Best Places to Buy Blue Diamonds Online (in 2023)

Sale Alert: James Allen, our #1 ranked online diamond retailer, is currently offering 30% OFF on diamond basics. Click Here to shop the sale and save big today.

Looking for the perfect place to buy blue diamond jewelry online?

You're in the right place! In this Learning Jewelry guide, I'll answer common questions like:

  • What should you look for when buying blue diamonds online?
  • Are blue diamonds good for an engagement ring?
  • How do you know you’re getting a good deal?
  • What are the red flags to watch out for when buying?
best places to buy blue diamonds online

Top 3 Best Places to Buy Blue Diamond Jewelry Online

If you need the list quick, here are my top picks for finding quality sapphires from reputable online dealers. Each shop can be considered a contender for the best place to buy diamonds from. Keep reading for more information about each of these shops.

  1. Blue Nile
  2. Brilliant Earth
  3. James Allen

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. 

Read also: Which diamond labs should you avoid?

#1 Buying Blue Diamonds at 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

Sale Alert: James Allen, our #1 ranked online diamond retailer, is currently offering 30% OFF on diamond basics. Click Here to shop the sale and save big today.

#2 Buying Blue Diamonds at 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. 

A lot of people don't know they sell colored diamonds. They have a section for natural blue diamonds, but they don't currently have any available. They do carry 60 lab created 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

#3. Buying Blue Diamonds at 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

Blue Diamond FAQs

Are Blue Diamonds Good for an Engagement Ring?

Any diamond is ideal for an engagement ring. On the Moh scale of mineral hardness, diamonds reach a 10, making them the most dirt and scratch resistant mineral around the world. 

Diamond is the best gemstone for everyday wear. 

Moh scale of mineral hardness

Image by the National Park Service. Public Domain.

If your blue diamond has been treated, it should still be able to be worn every day, so long as it hasn't been altered by a coating.

Coated diamonds can make their color grades look 2-4 grades better, but can fade in the presence of alcohol. 

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.

What Should You Look for When Buying Blue Diamonds Online?

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.

What Are the Red Flags When Buying Blue Diamonds Online?

One thing you want to look out for when buying blue diamonds online are blue diamond simulants. Simulants are different manmade or natural gemstones that basically pose as other gemstones.

Cubic zirconia (CZ) is a very common simulant that can be a rainbow of color representing various colored gemstones. It is commonly referenced in headlines or descriptions as "diamond CZ", but isn't a diamond. If the title says the word simulant in it, it is not a genuine blue diamond. 

Read also: What are the most common diamond substitutes?

The other common simulant for gemstones is glass, which can be faceted to be imitations in dealer markets. 

Any natural and untreated blue diamonds should always be expensive. There is no such thing as a great deal on a blue diamond. 

Treated blue diamonds are very popular in fashion jewelry and are often accompanied with a blue rhodium to enhance color. You can find small heat-treated blue diamonds as melee stones in sterling silver fashion jewelry for under $200. But the blue shade of a lab-created looks more artificial. 

How Do You Get the Best Deal When Buying Blue Diamonds Online?

I'm going to leave you with a couple lasting tips to remember when buying blue diamonds online. 

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

Know the treatments

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 celcius 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.

Sale Alert: James Allen, our #1 ranked online diamond retailer, is currently offering 30% OFF on diamond basics. Click Here to shop the sale and save big today.

Meet Your Jewelry Expert

Learn More About Jewelry

Want to learn more about jewelry? Check out these other helpful resources written by our jewelry experts!

Ask Your Jewelry Question Here

We are a team of jewelry experts who will teach you to identify scams and avoid spending money on features you can’t see.

Tell us as much information as possible to help us help you (ie, budget, preferences, etc.)