Uncovering the Secrets of Fluorescence in Lab Diamonds

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Lab-grown diamonds are becoming increasingly popular for those looking to purchase a diamond that is both ethically and economically conscious. But, there’s more than meets the eye when it comes to lab-grown diamonds—especially with fluorescence in lab diamonds playing an important role. So, what exactly does this mean? How can shoppers identify and save on these precious stones? We look at all these questions related to fluorescence in lab diamonds, so you have the information needed before making your next jewelry purchase!

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What is Diamond Fluorescence?

Fluorescence is a natural phenomenon that occurs when some materials absorb light energy from one wavelength and then reemit it as visible light at another wavelength.

Diamond fluorescence is a natural phenomenon occurring in some diamonds, including lab-grown diamonds. It is caused by the absorption of invisible ultraviolet light and the subsequent release of visible light. As a result, some diamonds will emit a soft glow or fluorescence when exposed to UV radiation, such as sunlight or black light. The strength of this fluorescence can range from faint to very strong.

Uncovering the Secrets of Fluorescence in Lab Diamonds

This effect is caused by submicroscopic structures within the diamond’s crystal lattice. The most common color emitted is blue, but other colors such as yellow, green, orange, and white can also be seen.

The Gemological Institute of America (GIA) has identified five levels of fluorescence:

  1. None
  2. Faint
  3. Medium
  4. Strong
  5. Very strong

It should be noted that the strength of fluorescence does not necessarily correspond with either clarity or color grade; two diamonds with completely different grades may still exhibit precisely the same level of fluorescence.

What is Lab Diamond Fluorescence?

Blue fluorescence, in particular, is associated with nitrogen atoms aligned in specific arrays within the carbon lattice structure inside a diamond’s crystal structure. Diamonds exhibiting strong blue fluorescence may appear hazy in regular light due to their unique internal composition.

History of fluorescence in lab diamonds and natural diamonds

History of fluorescence in lab diamonds - glow sticks exhibit the same effect.

The term “fluorescence” was first used in the late 19th century to describe the phenomenon of certain materials emitting visible light when exposed to ultraviolet radiation. In diamonds, fluorescence results from trace amounts of nitrogen atoms within the diamond’s crystal structure that absorb UV radiation and then emit visible light as they return to their ground state.

Early on, gemologists began using fluorescence as an identification tool for mined and lab-grown diamonds. By looking at how a diamond reacted under UV light, it could be determined whether or not it was mined or lab-created. This method became especially useful during World War II when lab-grown diamonds were produced en masse for industrial use.

Technological advances have allowed scientists to further study and understand fluorescence in both mined and lab-grown diamonds in recent years. For example, researchers have developed new techniques for measuring fluorescence intensity in different types of stones, which can help determine their origin more accurately than ever before.

That is crucial since lab-grown diamonds can also be fluorescent, but relying on the presence of fluorescence alone is not an accurate indicator of diamond origin.

Next, in our guide to fluorescence in lab diamonds, we’ll look at fluorescence in lab-grown diamonds.

Fluorescence in lab diamonds

Fluorescence in lab diamonds

Lab-grown diamonds are becoming increasingly popular for their beauty and affordability. In this section, we’ll explore how fluorescence affects lab-grown diamonds specifically and what you need to know before buying a fluorescent lab-grown diamond.

Lab-grown diamonds are no exception when it comes to exhibiting fluorescent properties – they, too, have been known to luminesce under UV lighting conditions, just like mined diamonds do. However, as we’ll explain below, lab-created diamonds display fluorescence much less frequently.

Lab-grown diamond shoppers should therefore keep an eye out for any potential signs of fluorescence before making their purchase decision, as it could affect how well the lab diamond appears in certain lighting conditions or even its overall value depending on its intensity level!

Fluorescence in lab-grown diamonds is most often due to the heating and radiation process. This can be employed to further a specific fancy diamond color, leading to the diamond reacting to UV light. When a diamond is exposed to radiation, the carbon structure is affected, and it can lead to gaps in the carbon structure. These gaps, in turn, absorb and reflect light differently, displaying the typical blue fluorescence. As with mined diamonds, fluorescence can also be caused by the presence of nitrogen, and the effects can highlight each other.

How does fluorescence affect lab-grown diamonds?

The presence of fluorescence can have positive and negative effects on the appearance of a lab-grown diamond, depending on its color grade.

Generally speaking, lower color grades such as K through M may benefit from having strong fluorescent properties since it helps mask any yellow tinting present in these stones—making them appear whiter than they actually are.

On the other hand, higher color grades such as D through F, even J, should avoid having too much fluorescence since it could make them look hazy or milky instead of clear and brilliant like they should be at those levels of quality.

That said, fluorescence may be hard to see with the naked eye and under normal light conditions. You would typically be unable to spot fluorescence in lab diamonds in an image or at a jeweler. So make sure you shop from one of the best places to buy lab diamonds, which have risk-free returns, should you be unhappy with your florescent lab diamond.

Here’s an example of two lab-grown diamonds from Ritani, only one of which is fluorescent (Ritani is one of our favorite places to buy lab-grown diamonds).

Example of two lab-grown diamonds from Ritani, only one of which is fluorescent

Understanding how fluorescence affects lab-grown diamonds is essential when considering whether or not a particular stone would suit your needs best – especially if budget constraints come into play!

Fluorescence in natural vs. lab-grown diamonds

Mined diamonds and lab-grown diamonds have different properties when it comes to fluorescence. Mined diamonds are more likely to exhibit some types of fluorescence, while lab-grown diamonds often do not. And when they do, it’s usually caused by radiation and heating – and in some cases, intentionally.

In mined diamonds, a wide range of possible types of fluorescence can occur due to trace elements present in the diamond’s structure. These include blue, yellow, green, orange, or red fluorescent hues, which may be visible under ultraviolet light.

One of the above diamonds exhibits strong fluorescence, while the other has no fluorescence.

Can you guess which?

1-carat, D-color, and VVS2 clarity diamond. Is it fluorescent?
1-carat, D-color, and VVS2 clarity diamond. Is this one fluorescent?

Both the above diamonds are 1-carat, D-color, and VVS2 clarity (mined, hence the hefty price tags) and from James Allen, one of our top-rated diamond jewelers.

Did you get it right? It’s the first one! But’s it only visible under certain light conditions and often impossible to see in a photo or a jewelry store.

While fluorescence occurs in about 30% of mined diamonds, most lab-grown diamonds will not display any fluorescence at all because they lack the trace elements that cause this effect in natural stones. But, as we have learned, fluorescence can occur in lab-grown diamonds, too, contrary to what some claim.

Why lab diamonds rarely exhibit fluorescence

Fluorescence is a unique property that can affect the diamond’s color and value. Natural diamonds often exhibit fluorescence, but lab-grown diamonds rarely do.

So why do lab diamonds rarely exhibit fluorescence?

The primary reason for the lack of fluorescence in lab-grown diamonds is due to their production process. During the growth process, nitrogen atoms are introduced into the crystal lattice structure of synthetic stones as part of their creation process; however, these nitrogen atoms do not absorb UV radiation like those found naturally occurring within mined stones.

When lab-grown diamonds do fluorescence, it’s often deliberately and in an attempt to promote a fancy color in a diamond.

When lab-grown diamonds do fluorescence, it's often in an attempt to promote a fancy color in a diamond.

Therefore, compared with their mined counterparts, most laboratory-created gems have little or no detectable levels of fluorescence. However, that does not mean you should not be aware of fluorescence. On the contrary, it may even be beneficial, as we will look into next in our guide to fluorescence in lab diamonds.

In Summary: The presence of fluorescence in lab diamonds can significantly impact their appearance. Mined diamonds may display faint to intense fluorescence in blue, yellow, green, orange, or red hues. Lab-grown diamonds typically lack these trace elements and rarely exhibit any fluorescence. However, fluorescence occasionally occurs in lab-created diamonds, so it’s essential to be aware of fluorescence.

Now, let’s look at tips to identify and save on lab-grown diamonds with high fluorescence.

Benefits of buying a fluorescent lab-grown diamond

  • One advantage of purchasing a high-fluorescent lab-grown diamond is that they tend to be less expensive than non-fluorescent stones since demand is lower. This is especially the case with higher color grades (near colorless diamonds) in which fluorescence may cause visible tints or shades.
  • Another benefit of fluorescence in lab diamonds is that for lab diamonds with lower color grades, which have a yellow tint, the presence of blue fluorescence may actually make the color appear cleaner and less yellow!
  • Lastly, you may appreciate the fluorescent effects caused by fluorescence in lab diamonds. They are often not visible, but when they are, it can be a dazzling effect that makes your diamond stand out from the crowd!

6 Tips to save on lab-grown diamonds with fluorescence

When shopping for lab-grown diamonds with fluorescence, there are several ways you can save money without sacrificing quality:

  • Look for stones graded K through M if you want maximum savings – The presence of strong fluorescent properties will help hide any yellow tints present in these lower-color grade stones, making them appear whiter than they actually are—which means you get more bang for your buck!
  • Avoid high color grades – diamonds graded D through F should generally not have too much fluorescence since it could make them look hazy or milky instead of clear and brilliant. However, this is not the case for all diamonds, so if you can find a diamond with a higher color grade that is not negatively affected by fluorescence, you could get a fantastic bargain.
  • Choose a lab-grown fluorescent diamond instead of a mined one and save 60-80% according to our latest price comparison between lab and mined diamonds. Lab-grown diamonds are chemically, physically, and optically identical to their mined counterparts but without the environmental impact.
  • If you want an affordable lab-grown diamond but don’t want one with too much fluorescent material present, then consider looking for one rated faint or very slight since these will still offer good value without compromising too much on quality due to their low-intensity fluorescence.
  • Buy at one of our recommended best places to buy lab-grown diamonds. We all highly rated these, and you’ll find the most extensive inventory of the highest-quality diamonds at the lowest possible prices without sacrificing customer service or the buying experience. Scroll down to see our list of the best lab-grown diamond jewelers.
  • Shop during a sale or use a discount code to save on your fluorescent lab diamond purchase (or any lab diamond). See our list of current sales, deals, and discounts on diamonds.

Some lab-grown diamonds may be slightly discolored due to their high fluorescence levels, while others may appear brighter and more vibrant in certain lighting conditions. Additionally, it’s also essential to look at other aspects, such as clarity, cut, and carat weight, before making your purchase decision.

In Summary: When shopping for a fluorescent lab-grown diamond, look for stones with a low color grade for the least impact. Or for a higher color grade for the most significant savings, but make sure the diamond does not appear cloudy or milky. To be safe, consider a diamond on the low end of the fluorescence scale. Always opt for lab-grown diamonds to save compared to mined ones, buy only from recommended retailers, and look out for sales.

Lab-grown diamond fluorescence FAQs

Why do lab diamonds fluoresce?

Lab-grown diamonds fluoresce when exposed to ultraviolet light due to the presence of nitrogen atoms in their structure. This is a common phenomenon among lab-grown and natural diamonds, which can be used to distinguish between them. Fluorescence is caused by energy absorbed from UV light and released as visible light. The color of this emitted light depends on the type and concentration of nitrogen present in the diamond’s crystal lattice structure. As a result, lab-grown diamonds typically emit a blue fluorescence, while natural diamonds may exhibit a variety of colors.

Is it good to have fluorescence in a lab diamond?

It depends on the individual’s preference. Fluorescence is a natural property of diamonds that can cause them to emit a soft glow when exposed to ultraviolet light. Some people prefer this effect, while others may find it distracting or undesirable. Ultimately, it comes down to personal taste and desire for your diamond purchase. It is important to note that fluorescence does not affect the value of a diamond; therefore, if you like the look of fluorescent diamonds, they can be an excellent choice for your jewelry needs.

Should I buy a lab diamond with faint fluorescence?

Whether you buy a lab diamond with faint fluorescence depends on your preferences and the diamond color grade. If the diamond color grade is low (such as a K grade), then some presence of blue fluorescence might counter the yellow glow and make it appear clearer. However, fluorescence may sometimes make the diamond appear slightly cloudy in diamonds of high color grades. In some cases, you could get a great deal if you accept some level of fluorescence, but consider how the diamond looks in different light settings before making your decision.

Do CVD diamonds have fluorescence?

Yes, CVD diamonds can have fluorescence. This is due to the presence of nitrogen atoms in the diamond’s crystal lattice structure which absorb energy from ultraviolet light and emit visible light. The intensity of this fluorescence can vary greatly depending on the type and concentration of nitrogen present in the diamond. In general, CVD diamonds tend to have lower fluorescence levels than natural diamonds, but some may still show faint or moderate levels of them.

Do HPHT diamonds have fluorescence?

Yes, HPHT diamonds have some degree of fluorescence, just like mined diamonds. However, because these stones are manufactured rather than naturally occurring, there is more control over the environment in which they are grown, affecting their level of fluorescence and other characteristics, such as clarity and color grade. Generally speaking, HPHT diamonds tend to show less intense fluorescence levels than mined stones due to the controlled growing environment they experience during production.

How does fluorescence affect diamond color?

The color emitted by fluorescent diamonds depends on their type and origin. For example, mined diamonds tend to emit blue or yellowish hues but may also display different colors, such as green, orange, pink, purple, or red, depending on their composition and growth environment. Generally speaking, stronger fluorescences are more likely to affect diamond color than weaker ones since they produce brighter hues that can overpower other shades present in the diamond’s color.


In conclusion, fluorescence in lab diamonds is a crucial factor to consider when shopping for lab-grown diamond jewelry. Lab-grown diamonds can have a wide range of fluorescence levels, from faint to strong, and it’s important to understand the differences between natural and lab diamonds. By understanding how fluorescence affects a diamond’s color, value, and appearance, you can make informed decisions when purchasing your dream diamond or jewelry piece.

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Rolf Hartmann
Rolf Hartmann

Rolf Hartmann has decades of experience in the jewelry industry. He knows everything you need to know to find the perfect diamond. He's an expert in lab-grown diamonds and has followed the exciting development of lab diamonds from industrial usage to the incredible gemstone quality that lab-grown diamonds are today. Rolf guides you to find the right diamond at the best possible price and expertly and transparently reviews all lab-grown diamond sellers.

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