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All You Ever Wanted To Know About Blue Diamonds
Updated December 2025
Forget the idea diamonds are clear, sparkling and well behaved. They're not always diamond shaped, they're not always crystal clear (hello salt and pepper diamonds), and they definitely aren't always white.
Have you met your first blue diamond yet? If you can't remember, you probably haven't. They have a way of staying in your mind. Natural blue diamonds are rare. Most blue diamonds people see today are color enhanced or irradiated blue diamonds.
But first! Let's be clear. Blue diamonds are real.
Since the supply of natural blue diamonds is so limited and the demand has skyrocketed, most blue diamonds on the market have been color enhanced. Does it make them fake or synthetic? Absolutely not! They're as real as can be, they've just gone through a quick makeover.
Diamond color treatments have been around since 1904, when a curious Sir Crookes experimented with radium salts and watched a diamond turn green. His results were patchy. Today’s results aren’t. Modern treatments can brighten, deepen or completely shift a diamond’s color in a controlled, predictable way. That’s why color enhanced blue diamonds are far more accessible than natural blue stones.
If you want to know what makes a diamond turn blue, how irradiation changes color, or whether treated blue diamonds stay blue for life, you’re in the right place. Let’s get dive into these mermaid colored stones.
HOW do diamonds turn blue?
The traditional white (or technically colorless) diamonds we’re most familiar with are created by nature’s longer term wizardry process, involving super heated, highly pressurized carbon molecules close to the Earth’s core. Nature also makes green and blue diamonds by exposing them to natural radiation deep under the Earth’s surface. These natural processes work on the same scientific principles that labs use to create blue diamonds, but nature takes the slow route and labs take the shortcut.
This radiation shifts the position of atoms within a diamond’s crystal structure and is what makes a diamond blue or changes it into another color.
It's all (not so simple) chemistry. Diamonds change color when their environment changes. The mermaid shape is just them showing off.
Irradiation is the fancy word for exposing a stone to radiation.
Modern day irradiation processes has revolutionized color treatments for gemstones.
Modern day irradiation processes have revolutionized color treatments for diamonds and other gemstones. Scientists have refined the process to create vivid, consistent, stable colors.
There are four processes to change a diamond’s color through irradiation: cyclotron, gamma rays, electron and neutron bombardment.
Cyclotron
In 1942, scientists at the University of Michigan put some diamonds in a cyclotron (a type of partile accelarator) and bombarded them with heavy radiation of protons and deuterons to turn regular diamonds into vivid green stones.
After a short quarantine period to get rid of any leftover radioactiveness, the world had its first safe to wear artificially colored diamonds!
The color from cyclotroned treated diamonds were uneven and depended largely on the direction of the treatment. This method is rare nowadays.
Gamma rays
Gamma ray treatment through exposure to cobalt-60 produces a blue to blue-green color that penetrates the entire stone.
Even though it's the cheapest and safest method of irradiating diamonds, it's also the longest, and can last for several months. This method is quite uncommon these days.
Scientist have refined the irradiation to a process that’s more common today, by blasting diamonds with high energy neutrons or electrons. These modern processes are safer and bring out the most vivid and even colors.
Electrons
A bombardement of neutrons from a reactor are ‘fired’ at the diamond. It gives a deep color, as the beam penetrates the entire stone.
Neutron
The diamond is penetrated about 1 millimeter deep, while it’s exposed to tiny high-energy electrons.
Scientists and diamond nerds have tried to copy this process from nature for over a century. Color enhanced diamonds are real diamonds exposed to similar radiation to create treated blue diamonds and other color, but over a shorter period of a time, and in a lab. The radiation can enhance, change, or brighten stones to all sorts of colors like pink, blue, green, yellow, red, purple and orange. So color treated diamonds are not grown in a lab, just treated. Think of it like dying your hair pink or blue. It’s still your real hair.
Color treated diamonds tend to start their life as diamonds with 'undesirable' colors, like pale yellows or browns. They are either dramatically enhanced (e.g. from a pale yellow to vivid yellow) or changed completely.
Irradiated diamonds are not lab created diamonds. They're natural and real diamonds that have been color treated.
After a purely experimental phase of changing diamond colors in the early 1940s, diamonds colored using irradiation flooded the market in the 1950s. As there was no simple test to distinguish hues created in nature from those changed in a lab, the market for colored diamonds crashed. Nowadays, a simple test using spectroscopes can tell natural from irradiated diamonds (each shows different spectra or light absorption characteristics).
Diamonds are forever. Is a blue diamond also forever blue?
Irradiation is non-nuclear and leaves no kind of residual radiation behind. The color change is permanent. If you're wondering if blue diamonds stay blue, the blue color is stable and irreversible under normal wear and tear.
The color is not affected by chemicals, ultrasonic cleaners, steam cleaning or polishing. Only when exposed to extremely high temperatures (like the 900 degrees Celsius fire blowing out of a jeweler's torch) blue and green colored diamonds may fade or even turn yellow.
Under normal circumstances, your diamond wouldn’t come in touch with such high temperatures. So this is only relevant when you’re taking your ring in for its annual checkup like prong repairs, resizing, cleaning or any other service.
Please be sure to tell your jeweler if your diamond has been irradiated. Your jeweler will know to take the appropriate precautions. Natural colored diamonds on the other hand are unaffected by heat.
Because this process is permanent, the GIA will grade and certify irradiated diamonds and can also laser inscribe the diamond to notify any potential buyer the diamond has been irradiated.
Are irradiated diamonds safe?
Out of all of the gemstone treatments currently on the market, irradiation is the one treatment that always raises questions. When the words 'irradiation' are whispered, the first thing that springs to mind is, ‘is it safe’? The good news is: yes it is!
Blue diamonds are safer to wear than a porcelain crown
All diamonds have been exposed to natural radiation over the millennia before man unearthed them, so technically all colored diamonds have been irradiated. And this exposure doesn't make them radioactive.
Irradiation changes a diamond’s color and it's the only diamond treatment that exists in nature as well as in laboratory conditions.
Radiation is measured in millirem, also called Radiation Absorbance Dose. We’re all exposed to small amounts regularly. Think intercontinental flights, medical scans, even the glow of your TV at night.
To put things into perspective, compared a large 6 carat blue topaz to common sources of radiation exposure. Blue topaz is often irradiated to achieve its color, so it’s a useful stand in for diamonds too. If a gemstone that size gives off a tiny amount of residual radiation, then the much smaller irradiated diamonds people actually wear give off even less.
For example:
A dose of wearing a blue topaz for one year = 0.03 millerem
Wearing porcelain crown or false teeth for one year = 0.07 millerem
Chest X-ray = 60 millerem (2000x that of topaz)
Irradiated blue diamonds pose no health risk. They are safe to wear every day and stable in color. There have been no reported cases of anyone being harmed by wearing irradiated diamonds or any other irradiated gems.
Full disclosure: The truth about blue diamonds
Most irradiated diamonds have a very particular coloring to them that can be easy to spot once you've seen enough of them. You can look for certain terms used to describe them. Irradiated diamonds will always be used on official trade documentation and diamond grading reports. The termscolor enhanced andtreated for color are more widely used in the market.
With regard to irradiated stones, your jeweler should tell you whether the gemstone you’re looking at has been treated. This is really important, as treated gems may need special care. It may also significantly affect the value of the gemstone. All irradiated diamonds should have a full disclosure and must be presented as being color enhanced.
What else do you need to know about blue diamonds?
Blue diamond colors
Blue, black, green and yellow are the most popular colors produced using diamond irradiation. Orange, red, purple and pink colors are also possible, but more difficult to produce.
Additional treatments
The overall clarity or imperfections of irradiated diamonds won't change with irradiation, but it can hide or disguise certain imperfections. Pretty much the same way a blue dress won’t look stained as easily as a virgin white dress. Irradiation may be followed by a high pressure, high temperature treatment to improve the stone’s clarity.
Advanced technology has enabled the jewelry industry to improve the visual appearance of lower grade diamonds by the process of laser drilling or fracture filling. This practice is referred to as clarity enhancement.
Laser drilling, and fracture filling treatments in diamonds are considered to be huge alterations. So much so, they're no longer considered natural diamonds.
Blue diamond meaning and symbolism
Blue diamonds symbolize truth, wisdom and devotion. The kind of devotion that feels steady, not clingy. They’re also tied to clarity and emotional depth, which makes sense for a gemstone that looks like a moment of calm right before the ocean pulls you in.
Some believe blue diamonds offer protection and resilience. Others simply love them because they’re beautiful, rare and look excellent next to a cup of coffee and a to do list you fully intend to finish someday.
So to sum it up, irradiated diamonds are natural and real diamonds, not lab created diamonds. They've been treated using radioactivity and are safer to wear than a porcelain crown.
HOW MUCH DO BLUE DIAMONDS COST?
Natural blue diamonds sit in a completely different price universe. They can range from expensive to astronomical, depending on color saturation, size, clarity and whether or not they come with a backstory involving royalty, mining legends or a suspiciously well timed volcanic event.
Color enhanced blue diamonds are probably the only blue diamonds us common folks can afford. Radiation makes diamonds more visually appealing and more affordable, but they should not be considered investment purchases. Buy the diamond because you love it, not because you plan to resell it for a yacht and a baby goat.
Color enhanced blue diamonds are far more affordable. Their price depends on how vivid the color is, how evenly the color spreads, whether any additional clarity treatments were used and the base quality of the diamond before treatment.
A natural fancy vivid blue diamond might sell for the price of a house. A treated blue diamond might sell for the price of a vacation, a bicycle or a very enthusiastic grocery run involving cheese.
Blue diamond value
Does the value of a diamond change after enhancements? A treated blue diamond is worth far less than a comparable untreated stone, simply because it is much faster and easier to achieve this color in a lab than to wait for nature to pull off one of its rare tricks.
Buy a treated blue diamond because you love it, not as an investment
HOW to choose a blue diamond you feel good about
You might expect a buying guide here, but let’s be honest. We don’t specialize in high end natural blue diamonds. Those are rare creatures with price tags that live in a different tax bracket.
What we do offer is something more grounded.
If you’re drawn to blue diamonds, choose one for its color, its character and the way it makes you feel. A soft denim blue. A vivid lagoon blue. A teal flash that catches the light and does its own tiny dance. Let the color guide you, not the prestige.
A natural blue diamond is breathtaking, but a color enhanced blue diamond can be just as fun, meaningful and personal. It all depends on what you want on your finger, your neckline or your nightstand next to your half finished books.
If you ever want a second opinion or a reality check, we’re happy to help. We love honest conversations about gemstones, expectations and budgets.
Blue Diamond Jewelry
We don't have a lot of blue diamonds in stock, so grab one before it goes!
blue diamond faq
Are blue diamonds real?
Yes. Natural blue diamonds exist, but they are extremely rare. Most blue diamonds on the market today are natural diamonds that have been treated to enhance or change their color.
What makes blue diamonds blue?
Natural blue diamonds get their color from boron. Treated blue diamonds get their color from rearranged atoms caused by irradiation.
Are irradiated diamonds safe?
Yes. They contain no harmful radiation. In fact, your porcelain dental crown likely exposes you to more radiation than your blue diamond ever will.
Do blue diamonds change color?
Not under normal conditions. High heat from jewelry repairs may affect the color of treated stones, so tell your jeweler if your diamond has been irradiated.
Are natural blue diamonds rare?
Very. Naturally blue diamonds are among the rarest diamonds in the world. Only red diamonds and a handful of violet diamonds outrank them on the rarity scale. Color enhanced blue diamonds, however, are abundant. That’s good news for anyone who loves the color but not the price tag of a natural blue diamond.
Do blue diamonds make good engagement rings?
They can. Natural ones are prized for their rarity. Treated ones are prized for their color.
Do diamonds show up on X rays?
Yes, but not in a way that affects their safety or wearability. Most hard materials show some level of density on X rays. Your diamond will not glow, hum or do anything dramatic.
Read on to learn more about diamonds. Or build your own custom diamond ring with a diamond in the shape and color of your choice.