When shopping for diamond jewelry, it can be overwhelming to navigate the various options available. Even seemingly identical stones can differ in price and quality due to factors such as how they sparkle and appear under UV light. One element that can impact a diamond’s brilliance is fluorescence.

In this article, the subject of whether diamonds should fluoresce or not will be explored. The article will cover what fluorescence is, what causes it in diamonds, how to check for it, and the pros and cons of purchasing a diamond with fluorescence. By the end of the article, readers will have a better understanding of how fluorescence impacts a diamond’s quality and whether it is a factor to consider when making a purchase.

Key Takeaways

  • Fluorescence can impact a diamond’s brilliance and quality.
  • There are pros and cons to purchasing a diamond with fluorescence.
  • Understanding fluorescence can help inform diamond purchasing decisions.

Should a Diamond Have Fluorescence? What Is It?

Fluorescence is a natural occurrence in diamonds, with up to 30% of all diamonds having some degree of fluorescence. It is the tendency of diamonds to emit a soft-colored flow when exposed to UV light, such as visible or black light. The degree of fluorescence in a diamond can differ, with most diamonds having a fluorescence level graded as faint, medium, strong, or very strong. However, some diamonds have no fluorescence, and these are considered to have the best natural color properties, making them the most expensive stones.

The impact of fluorescence on a diamond’s appearance depends on the degree of fluorescence and the diamond’s color grade and clarity. Faint or none fluorescence does not affect the appearance of diamonds much, but they may appear slightly hazy. In contrast, medium-blue fluorescence in higher color grade diamonds, such as G grades or higher, can give the diamonds a hazy or milky look. Strong and very strong blue fluorescence can result in very cloudy or hazy diamonds.

While fluorescence can improve some diamonds, others do not benefit from this quality, especially those belonging to the D, E, & F color grades, which are low-value diamonds. In the case of fluorescence in colorless diamonds that fall in the DEF color grades, the value of these diamonds will drop by about 15%. This is particularly true for diamonds with faint to medium fluorescence, which is also stones whose fluorescence is easily perceptible to gemologists when they view the stones under UV light.

However, the blue fluorescence glow in diamonds belonging to the I-M color grades is often an added advantage that increases the value of the diamonds. The interaction of the color blue and yellow, which is common in most diamonds, leaves you with diamonds that look much whiter and brighter. Therefore, medium, strong, or very strong fluorescence diamonds in the I-M color grades will be valued higher because these diamonds shine the brightest.

It is essential to be cautious when buying diamonds with strong blue fluorescence, especially for diamonds belonging to the D-F color grades or even the diamonds with a very strong blue fluorescence in the G-H color grades. These diamonds do not naturally have enough body of color to offset the high fluorescence, so they may not be ideal. Diamonds in the D-F color range are considered colorless naturally, while diamonds in the G-H color grades are near-colorless, and the I-M color diamonds are warm.

In conclusion, whether a diamond should have fluorescence or not depends on the individual’s preference. However, the degree of fluorescence and the diamond’s color grade and clarity should be taken into consideration when making a purchase. Fluorescence can either enhance or detract from a diamond’s appearance, and it is essential to be aware of its impact on the diamond’s value.

What Causes Fluorescence in Diamonds?

Fluorescence in diamonds is caused by the arrangement of nitrogen atoms in the submicroscopic structure of the crystal. The nitrogen atoms are aligned in a specific array in the carbon atoms’ lattice, resulting in the common blue fluorescence. This phenomenon is not a performance feature but an identifying feature of the diamond. The fluorescence may be good or bad, depending on the affected diamonds. The microscopic and submicroscopic structures in the crystals are responsible for the fluorescence in diamonds.

How to Check Fluorescence in Diamonds

To check for fluorescence in diamonds, one can use either direct UV light from a UV source or bright sunlight. Another option is to observe the diamond under black light. In the lab, gemologists use a set of fluorescent master diamonds viewed at specific angles under UV light to determine fluorescence. The viewing angle is crucial because fluorescence may occur only in specific or localized angles/zones in the diamond. This means that the fluorescence may be visible from one angle and less visible from another.

The emitted light or fluorescence can be directional or multidirectional under UV light. In some instances, the fluorescence is localized to multiple areas within the diamond, which may display distinct colors in these spots or even have a mixed color array. However, such characteristics are rare in diamonds.

To summarize, checking for fluorescence in diamonds is a simple process that involves observing the diamond under UV or black light. The viewing angle is important, and gemologists use a set of fluorescent master diamonds to determine fluorescence in the lab.

Are the Fluorescent Diamonds Cheaper?

Fluorescent diamonds are priced differently from non-fluorescent ones. The pricing of diamonds is entirely mathematical, but prices fluctuate due to the forces of demand and supply and the diamonds’ characteristics and make.

The warmer diamonds with strong fluorescence in the I-M color grades will go for a premium of 2 or 3% higher than the non-fluorescent I-M grade diamonds. This is because the warmer (yellow-hued) diamonds will have a positive interaction with the blue fluorescence that will cancel out, making the diamonds brighter, hence more expensive.

On the other hand, the D-H diamonds, whose color features are dampened by the very strong blue fluorescence, may save as much as 15% on these diamonds.

It’s important to note that some non-fluorescent white diamonds may cost less than the enhanced fluorescent ones. Therefore, it’s essential to consider the fluorescence level and color grade of the diamond before making a purchase decision.

In summary, fluorescent diamonds can be either cheaper or more expensive than non-fluorescent ones, depending on their color grade and fluorescence level.

How important is fluorescence in diamonds?

The importance of fluorescence in diamonds depends on the quality of the diamond and the level of fluorescence. Some diamonds may look better with fluorescence, while others may be negatively affected by it.

Pros and Cons of Diamond Fluorescence

Diamond fluorescence is a natural phenomenon that can affect a diamond’s value. Here are some of the pros and cons of diamond fluorescence:

I-M diamonds appear brighter with strong blue fluorescence, making them more valuable
Fluorescence can lower the value of colorless diamonds by adding a blue tint
Some fluorescent diamonds are cheaper than non-fluorescent ones
High fluorescence can result in hazy diamonds
G-H near colorless diamonds with faint fluorescence will be bumped up one color grade and appear even brighter
Fluorescence may not be noticeable to the naked eye
D-F fluorescent diamonds are up to 15% cheaper

Overall, diamond fluorescence can have both positive and negative effects on a diamond’s value. It’s important to consider the level of fluorescence when purchasing a diamond and to choose one that suits your preferences and budget.

Should You Buy a Diamond with Fluorescence?

The decision to buy a diamond with fluorescence depends on the level of fluorescence and its impact on the diamond’s appearance. If you are looking to save money on colorless diamonds, buying fluorescent D-H diamonds may be a cheaper option, provided you don’t mind the blue spark on the diamond. However, it is advisable to avoid diamonds with medium, strong, and very strong blue fluorescence as they tend to look hazy. Ultimately, the decision to buy a diamond with fluorescence depends on personal preference and budget, and it is recommended to view the diamond in person before making a purchase.

Cheaper option for colorless diamonds
May look hazy with medium, strong, and very strong blue fluorescence
Unique blue spark
Personal preference may vary
Recommended to view in person before purchasing

Overall, it is important to weigh the pros and cons before deciding whether to buy a diamond with fluorescence.


When it comes to buying diamonds, it’s important to consider the level of fluorescence and how it affects the appearance of the stone. Some diamonds may appear hazy while others may be whiter and brighter due to fluorescence. It’s crucial to inspect the diamonds before making a purchase and avoid stones whose color features are negatively altered by fluorescence.

However, if you don’t mind some haziness and are looking for a small price cut, heavily fluorescent stones may be a good option for you. Ultimately, the decision of whether to buy fluorescent or non-fluorescent diamonds depends on personal preference and the desired appearance of the stone.

Tiger, a fashion and jewelry expert, recommends taking the time to determine what you want your diamonds to look like before making a decision. By doing so, you can ensure that you are satisfied with your purchase and that your diamond meets your expectations.