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What Is Fluorescence in a Diamond?

by Clean Origin
Last updated on August 21, 2023

What is fluorescence in a diamond? The answer might surprise you. Diamonds are a natural beauty that we all secretly long for. But when it comes time to shop for one, there’s so much flashy jargon and terminology that can confuse the buying process. You may see the word fluorescent diamonds and wonder exactly what is fluorescence in a diamond. You’ll learn everything you need to know about diamond fluorescence in this article to get on with picking your dream ring!

Fluorescence is the glow you see when an object emits visible light. Some diamonds fluoresce or glow when exposed to ultraviolet (UV) rays from sources such as the sun and fluorescent lamps. 

As a result, they may emit a bluish light or, less frequently, a yellow or orange light. When you remove the UV light source, the diamond ceases to glow. Submicroscopic structures within the crystal cause diamond fluorescence. Scientists associate strong blue fluorescence with the presence of nitrogen atoms aligned in specific arrays within the carbon lattice. 

Diamond fluorescence refers to the intensity of a colored glow that you can see when you expose a diamond to UV light. In some instances, diamonds with fluorescence may look milky and lifeless in daylight, but in most cases, even strong fluorescence rarely affects the appearance of a diamond.

Fluorescence is simply an identifying characteristic rather than a performance characteristic, and thus fluorescence is neither good nor bad. In some cases, fluorescence can cause particular diamonds to appear cloudy, reducing their transparency and brilliance. Jewelers frequently describe these diamonds as oily, hazy, or milky. It isn’t good in these cases.

A study performed in 1997 by the GIA found that the level of fluorescence has no widely perceptible effect on diamonds’ color appearance or transparency. 

How Does Fluorescence Affect Color Grade?

Loose Diamonds
Loose Diamonds

When viewed under fluorescent light, diamonds with very strong blue fluorescence can have a color grade two levels higher than their color under non-UV lighting. Strong blue fluorescence may be one grade different, and medium fluorescence may be different by a half grade. The effects of faint fluorescence are negligible.

Because the fluorescent glow is usually blue (which is the complementary color to yellow), fluorescence can make diamonds of I-M color appear up to one grade whiter. Of all the diamonds submitted to GIA for grading, approximately 25% to 35% show some fluorescence.

Alternatively, a J color diamond of any clarity and Medium fluorescence will typically sell for up to 2% more than a like diamond with no fluorescence. However, as we mentioned before, the difference is not bad, as the fluorescence may slightly enhance the visible color of a lightly colored diamond.

Diamond Fluorescence, Color, and Price

Asscher Cut Diamond

However, you may notice a price difference! Fluorescent diamonds are less expensive than non-fluorescent diamonds. Diamond merchants sell colorless diamonds, those with a color grade of D-F, at a discount if they have a fluorescent glow underneath a UV light. This is because they see the fluorescence as a flaw, so the diamond no longer holds the same value. Unlike white diamonds, though, most fancy-colored diamonds look better without or with just faint fluorescence grades.

Some jewelers say that fluorescence always harms your diamond’s quality and appearance. But here at Clean Origin, we believe that diamond fluorescence is actually more a matter of personal taste. If you understand it correctly, it can be your friend when you’re ready to purchase. 

For diamonds with faint or no fluorescence, this does not affect the natural appearance of the diamond. Still, a more fluorescent diamond glows in natural sunlight, too, and this is undesirable to some in a white diamond.

Sometimes, a diamond’s fluorescence will not affect its price, while at other times, it will. For example, according to the chart, an E color diamond with VS1 clarity and Strong fluorescence will tend to sell for 3-5% less than a like diamond with no fluorescence.

A Diamond with Strong Fluorescence


The exception would be to exercise caution in purchasing a diamond with fluorescence in D-F color or Very Strong fluorescence in G-H color diamonds (which do not possess enough body color to offset the fluorescence and strong blue). Fluorescence grades are none, faint, medium, strong, and very strong. 

Most diamonds exhibiting Strong Blue Fluorescence appear slightly to be severely hazy in regular lighting conditions. The vast majority of those are blue, but white, yellow, orange, medium blue fluorescence, and red fluorescence are also seen in rare cases. Medium blue fluorescence with a high color grade (G or better exposed to UV light):

You may think diamond fluorescence is good. You may like it, or you may not. If you are considering a fluorescent diamond, take the time to look at it under different kinds of lighting, including natural daylight, and compare it to other diamonds of the same color. Some trade professionals think blue fluorescence enhances a diamond’s appearance, especially with I to M color grades. Over 95% of loose diamonds that have fluorescence have blue fluorescence, meaning they will glow a pale blue when put under UV light.

Even faint fluorescence will add a dash of blue to your otherwise white stone. Therefore, an I-M diamond color will appear more like a higher-quality stone when it has a slight fluorescence. Fluorescence can make a color or yellow diamond appear white or a white diamond appear blue. Diamonds of strong or very fluorescence appeared to have better color than less fluorescent stones. The degree of fluorescence can vary as around one-third of all diamonds show some fluorescence.

How to Avoid Fluorescent Diamonds

Cushion Cut Diamond
Cushion Cut Diamond

Now that you know how fluorescence alters colors, you can decide if a fluorescent diamond is a right choice for your engagement ring. If you decide you want to avoid fluorescence altogether, lab grown diamonds are an excellent option for your engagement ring. 

Clean Origin exclusively carried lab-grown diamonds. You can design your dream diamond engagement ring with us by selecting a lab-created diamond and a ring setting. 

Lab-grown diamonds are 20-40% less expensive than traditionally mined diamonds. Lab-grown diamonds (also known as lab-created, artificial, engineered, and cultured diamonds) are grown in highly controlled laboratory environments. Advanced technological processes replicate the conditions which naturally develop when they form in the Earth’s mantle, beneath the crust.

Our lab-created diamonds are available in a variety of colorless ranges and fancy colors considered extremely rare in nature, such as popular shades of vivid yellow.

Environmental Issues Surrounding Diamond Fluorescence

Diamond Fluorescence
Diamond Fluorescence

Diamonds are diamonds regardless of where they come from, right? It depends on whether you’re asking a jeweler, a bride-to-be, or someone concerned about mining and manufacturing sustainability practices. While it may be difficult to distinguish a lab-grown diamond from a natural diamond, some significant differences in their origins may influence your purchase and from whom you purchase it. Natural diamonds are created by nature as a result of intense heat and pressure, formed over the course of millions of years.

Diamond mining also has many detrimental impacts on the environment, including soil erosion, deforestation, and ecosystem destruction. While mined diamonds have a negative environmental impact, lab-created ones have no such concerns. Nearly 100 square feet of land is disturbed for every carat of diamond mining. In addition, it produces almost 6000 lbs of mineral waste. In contrast, the process of creating lab diamonds does not disturb the land, regardless of carat size.

Diamond fluorescence is not a grading factor included in the GIA 4Cs ( color, clarity, cut, and carat weight ). If your stone gets a grade by the AGSL (American Gem Society Laboratories), you’ll have a fluorescence grade. Many elements in nature emit fluorescence, which causes its presence in diamonds.


Clean Origin Diamond Engagement Rings
Clean Origin Diamond Engagement Rings

Fluorescence refers to a diamond’s ability to emit a (soft) glow when exposed to ultraviolet light (UV light). The fluorescence effect is present in over 30% of diamonds and is essential to consider when purchasing a loose diamond. Fluorescence is present in a significant portion of the market. Most of those are blue, but white, yellow, orange, and red fluorescence can occur in rare cases.

A diamond’s beauty is in the eye of the beholder. A diamond with a strong or very strong fluorescence sometimes has a milky appearance. However, less than 2% of diamonds with a strong or very strong fluorescence grade exhibit this. When UV light strikes a diamond with fluorescent properties, the stone emits a glow. Diamonds with no or a faint fluorescence are rarer than those with a strong or very strong fluorescence.

Fluorescent diamonds sell at up to a 15% discount since the fluorescence is perceived as a defect. In fact, the visible effects of Faint to Medium fluorescence are perceptible only to a gemologist with special tools. Overall, diamond fluorescence should not be a significant factor in purchasing a diamond since its effects are negligible. 

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