Do Lab Diamonds Have Fluorescence?

An estimated one-third of diamonds have fluorescence, but do lab diamonds fall into this category? Get to know some facts and fiction about lab-grown diamonds on the hot topic of fluorescence.

What Is Fluorescence in a Diamond?

When talking about diamonds, fluorescence means a diamond emits a colorful glow. 95% of the time, this glow is blue when it is exposed to UV light. Less often, fluorescent diamonds might look yellow, green, red, or white.

Is Diamond Fluorescence Good Or Bad?

This is not inherently good or bad – some people like diamonds with fluorescence, and others prefer them without. It comes down mostly to personal choice.

Diamond Fluorescence Scale and Grading

The GIA has five categories on its diamond fluorescence scale:

1. None

2. Faint 

3. Medium

4. Strong

5. Very Strong

Depending on where they fall on this scale, diamonds will look different under UV light. For example, a diamond with grade 2 (faint) fluorescence will emit just a very small amount of (usually) blue under UV light. 

Higher up on the scale with a strong or very strong grade, you have diamonds that have a more intense blue color under UV light. Diamonds with greater fluorescent intensity might also look cloudy or milky to the naked eye.

How Fluorescence Varies in Lab-Grown Diamonds

Lab-grown diamonds fluoresce differently than natural diamonds and even vary based on the growth method used.

• HPHT diamonds tend to show a cruciform fluorescence pattern, which appears on the pavilion or crown of the diamond.

• CVD diamonds, on the other hand, typically display a striped fluorescence pattern due to the way they are grown in layers.
  
  

Unlike mined diamonds, lab diamonds tend to fluoresce more strongly under short-wave UV light rather than long-wave UV light. However, fluorescence alone is not an indicator of whether a diamond is lab-grown or natural.

Are Diamonds With Fluorescence More Expensive?

Fluorescence can sometimes work to the buyer’s benefit. For example, a nearly colorless diamond (a J diamond) could have the color quality of an H or J diamond, which also means nearly colorless but closer to totally colorless. 

In this case, you might not want to pay the price for a J diamond. These diamonds could then be priced more affordably, which means you still get an incredible diamond for a better price. However, many bigger, more expensive diamonds are worth more when they exhibit no fluorescence. 

In some cases, diamonds can actually appear whiter with more fluorescence, while others, as we shared above, can look cloudy or milky. This is not because the fluorescence makes the diamond hazy, but rather, it can increase pre-existing haziness.

For diamonds with a fluorescent grade of none or faint, fluorescence is less likely to be a pricing factor because the diamond’s appearance is not affected by it.

How Fluorescence Differs Between Mined & Lab-Grown Diamonds

While both mined and lab diamonds can exhibit fluorescence, their characteristics differ significantly. Fluorescence in lab diamonds is more predictable and customizable.

What Causes Fluorescence in Diamonds?

Diamond, which is pure carbon, has two core trace elements: boron and nitrogen. The presence of each of these elements can alter a diamond’s appearance. 

• Diamonds have a certain level of boron if the mineral is present in the earth when the diamond crystallizes. Under UV light, boron fluoresces.  

• The presence of nitrogen atoms can also lead to blue fluorescence because of how they align under the carbon lattice. 
  
  

Because lab diamonds are real diamonds, they can also fluoresce, even though they are grown differently than natural diamonds. 

Lab Diamonds and Fluorescence

Should a lab diamond have fluorescence? High–quality lab diamonds should not have a high grade of fluorescence. In some fancy-colored lab diamonds, fluorescence is more common. 

Jewelers often strive to create lab diamonds without nitrogen or boron, but a small amount of these minerals can still be present. In that case, a lab diamond can have fluorescence. In fact, it’s a common myth that lab diamonds do not have any fluorescence. While it could be less common in lab diamonds, it is certainly not impossible.

Should a Lab Diamond Have Fluorescence?

Some lab diamonds do have fluorescence, even though they are made differently than natural diamonds. Still, they are real diamonds, and real diamonds can fluoresce, which means lab diamonds can too.

Rather than focusing on whether a lab diamond has fluorescence or not, it’s more important to consider how this fluorescence alters the appearance of the diamond, if at all. 

Can Fluorescence Lead to Overgraded Color?

One concern among diamond buyers is whether fluorescence impacts how diamonds are color-graded in lab reports. Since grading is done under UV light conditions, fluorescence can sometimes make a diamond appear whiter than it actually is. This means a lab-grown diamond graded as an H color might visually appear closer to a G under UV light but look slightly different in normal lighting.

A study by GIA found that:

• Fluorescence had little to no impact on most diamonds’ visual appearance under standard lighting.

• However, in some cases, strong fluorescence made diamonds look slightly hazy or over-graded in terms of whiteness.

While this effect is rare, it's worth considering if you’re purchasing a diamond at the higher end of the color scale (D-G) and want to ensure its true color holds up across all lighting conditions.

Why Is My Lab Grown Diamond Glowing?

Lab grown diamonds can appear to glow under certain lighting conditions due to their unique fluorescence properties. This fascinating phenomenon is caused by submicroscopic structures within the diamond crystal. When nitrogen or boron atoms align in specific arrays within the carbon lattice, they often create the distinctive blue fluorescence many diamond owners notice.

Selecting Lab Diamonds With the Right Fluorescence

As for buying a lab diamond and accounting for its fluorescence, let's cover some of the key points to understand that will make this decision easier. 

 Understanding Fluorescence Levels

• None to Faint Fluorescence: Diamonds with no or faint fluorescence typically show little to no change in appearance under UV light. These diamonds are often more desirable and can be more expensive.

• Medium to Very Strong Fluorescence: Diamonds with stronger fluorescence might appear milky or cloudy in natural light, and they can be priced lower than diamonds with little to no fluorescence. 
  
  

Desirable Blue Fluorescence

Fluorescence isn’t necessarily a good or bad thing in a diamond. Sometimes, blue fluorescence makes diamonds look whiter than their actual color grade. This is advantageous in diamonds with lower color grades (e.g., H, I, J or K). 

Assessing Performance and Aesthetics

A diamond's fluorescence does not play nearly as big a role in a diamond’s sparkle as its cut does. A diamond’s cut performance is what gives a diamond maximum light performance, including its brightness, sparkle, and scintillation. 

A diamond’s shape and size will also determine if and how it exhibits fluorescence. A rough-cut diamond will often have more uniform fluorescence than a fancy shape. 

Shop Lab Diamonds With Superior Light Performance

Brian Gavin Diamonds’ lab diamonds are crafted with the same attention to detail as natural diamonds, so they meet the highest standards of brilliance and beauty. Our Premium Lab Diamonds are grown with optimal cut quality in mind, ensuring maximum light return and scintillation. Proprietary cuts and patented single-cycle CVD process result in diamonds that “wow” as visible perfection.

Each lab diamond is carefully selected to be sure they have desirable levels of fluorescence that do not negatively impact its appearance. Each diamond undergoes rigorous quality checks and grading to guarantee its exceptional performance and aesthetic appeal.