Diamond Fluorescence: Is it Good or Bad?

Last Updated on July 25, 2023 by Juli "Jewels" Church

When I first began delving into the fascinating world of diamonds, I was mesmerized by their brilliance, their ability to play with light in such a magical way. One particular attribute that caught my eye and piqued my curiosity was this peculiar phenomenon called diamond fluorescence.

diamond fluorescence

Now, fluorescence, in the broadest sense, refers to the ability of a substance to absorb light at a certain wavelength and re-emit it at a longer wavelength. In simpler terms, it's like having an invisible glow under certain types of light.

Let's translate this into the context of diamonds and begin our exploration of fluorescence.

When I first began delving into the fascinating world of diamonds, I was mesmerized by their brilliance, their ability to play with light in such a magical way. One particular attribute that caught my eye and piqued my curiosity was this peculiar phenomenon called diamond fluorescence.

Now, fluorescence, in the broadest sense, refers to the ability of a substance to absorb light at a certain wavelength and re-emit it at a longer wavelength. In simpler terms, it's like having an invisible glow under certain types of light.

Let's translate this into the context of diamonds and begin our exploration of fluorescence.

What is Diamond Fluorescence?

So what exactly is diamond fluorescence? Picture this: you walk into a club, wearing some sparkly diamond bling on your hand. All of a sudden under all that black light in the midst of that party atmosphere, your diamond begins to glow, exuding an ethereal light. This, my friends, is diamond fluorescence — the luminescent glow that some diamonds emit when exposed to ultraviolet (UV) light. The source of this mystifying glow? Tiny submicroscopic structures within the diamond, each of them acting like a miniature lightbulb, switching on under the influence of ultraviolet light.

Fluorescence in a diamond is not a universally observed phenomenon, though. Not all diamonds possess this "superpower". Around 25-35% of diamonds exhibit some degree of fluorescence, according to the Gemological Institute of America (GIA). The "show" can range from a faint fluorescence, barely perceptible glow to a dazzling, vibrant display, usually in colors ranging from bluish-white to yellow.

The science behind why some diamonds fluoresce and others don't? It boils down to their individual chemical composition and structure. The presence of certain elements like boron or nitrogen and defects in the diamond crystal lattice can contribute to a diamond's ability to fluoresce.

history of fluorescence in diamonds

For me, this variance in diamonds only adds to their allure. Each diamond is truly unique, carrying within it an atomic recipe for beauty that's been billions of years in the making. I can't help but be drawn to the glow of a fluorescent diamond, the story it tells, and the mysteries it holds. It's this very fascination that led me on a journey through time to discover how our understanding of fluorescence in a diamond has evolved.

History and Discovery of Diamond Fluorescence

As we step back in time, tracing the origins of our understanding of fluorescent diamonds, we journey into an era of curiosity, wonder, and scientific revelation. The phenomenon of fluorescence, named after the mineral fluorite known for its fluorescent properties, was first studied in the early 19th century by British scientist Sir George Gabriel Stokes. But its association with diamonds didn't emerge until later, as our understanding of these brilliant gems evolved.

In the early days, fluorescence was often mistaken for phosphorescence, a similar but different phenomenon where a material continues to glow even after the light source has been removed. This confusion, understandably, led to misconceptions about diamond fluorescence, leading some to see it as an undesirable trait.

As scientific advancements unraveled the mysteries of the atomic world, our understanding of fluorescence deepened. We learned that fluorescence is a quick response, a fleeting glow that disappears the moment the UV light source is switched off. Unlike phosphorescence, it's an instantaneous light show, adding an extra layer of intrigue to the already captivating allure of diamonds.

Today, our knowledge of diamond fluorescence paints a complex and fascinating picture, a testament to the wonders of nature and the journey science has taken in decoding it. From mistaken identities to an appreciated feature, the perception of fluorescence has truly evolved over the centuries.

Diamond Fluorescence and Its Impact on Diamond Quality

A question I often find myself mulling over is — how does fluorescence impact diamond quality? Does it enhance a diamond's appearance or diminish it? Let's dissect this by looking at two fundamental aspects — clarity and color.

Diamond Fluorescence and Clarity

Traditionally, the clarity of a diamond is determined by the presence of inclusions and blemishes, but fluorescence can sometimes interact with these factors in surprising ways. For instance, a strong blue fluorescence can make inclusions more visible in certain lighting conditions, affecting the overall clarity grade. However, this is quite rare and typically occurs only in diamonds with extremely strong fluorescence.

Diamond Fluorescence and Color

Fluorescence can also interact with a diamond's color. Blue fluorescence, the most common type, can help offset any yellowish tints in a diamond, making it appear whiter or colorless in UV-rich environments like sunlight or fluorescent lighting. On the flip side, it could potentially cause over-blueing in rare instances, imparting a hazy or oily appearance to the diamond. But it's important to note that this is quite rare and generally seen only in diamonds with very strong blue fluorescence.

Check out the F color and I color diamond below. Which appears whiter?

no fluorescence vs strong blue fluorescence

LEFT: An F color diamond with no fluorescence. RIGHT: An I color diamond with very strong blue fluorescence, as seen in indirect sunlight.

Is Diamond Fluorescence Good or Bad

Whether fluorescence is good or bad in a diamond is not quite clear cut. In some instances, fluorescence can enhance a diamond's beauty, and in others, it may not. Much like the mysterious glow it imparts, the impact of fluorescence on a diamond's quality is a nuanced interplay of light, chemistry, and personal aesthetics.

Positives of Diamond Fluorescence

  • Color Enhancement: As previously mentioned, when diamonds fluoresce blue, it can enhance the color of a lower-grade diamond with a yellowish tint. Under UV conditions (like in sunlight), the blue fluorescence can balance the yellow, giving the diamond a whiter or more colorless appearance.
  • Unique Aesthetic Appeal: For some people, the glow that a diamond emits under UV rays adds a unique aesthetic appeal, making the diamond more attractive and interesting. This can be especially appealing for those who want a diamond that has its own unique 'personality'.
  • Price: Diamonds with strong fluorescence are often priced lower than those without, especially in higher color grades (D, E, and F). If you're not bothered by fluorescence, this can mean a better deal for you.

Negatives of Diamond Fluorescence

  • Potential Over-Blueing: In rare cases, diamonds with very strong blue fluorescence can appear hazy or oily in daylight or under bright lights, which can impact their brilliance and transparency. This phenomenon, known as over-blueing, mainly affects diamonds in the top color grades.
  • Market Perception: The diamond market typically places a premium on diamonds without fluorescence. This is particularly true for diamonds with a color grade of H or higher. This means that diamonds with strong fluorescence can be harder to resell.
  • Influence on Clarity: In some cases, fluorescence can highlight the inclusions in a diamond, affecting its overall clarity.

Comparing Diamonds With and Without Fluorescence

A comparison between diamonds with and without fluorescence is much like a comparison between two distinct pieces of art; both hold their own unique appeal and value. In my explorations, I've found the differences to be intriguingly nuanced.

2 G color diamonds in natural ambient light

2 G color diamonds in natural ambient light

2 G color diamonds in direct sunlight

2 G color diamonds in direct sunlight

Under normal lighting conditions, the majority of fluorescent diamonds appear identical to their non-fluorescent counterparts. However, the story changes under UV light. Fluorescent diamonds emit a captivating glow, typically blue, but sometimes yellow, white, or another color. This phenomenon adds an extra dimension of beauty and intrigue to the diamond.

Interestingly, under ultraviolet light, a diamond with strong blue fluorescence can appear whiter or more colorless than a non-fluorescent diamond of the same color grade. It's like a hidden superpower that comes into play under specific conditions!

degrees of fluorescence

Diamonds with increasing degrees of fluorescence under UV light

Non-fluorescent diamonds, on the other hand, retain their color regardless of the lighting situation. They might not glow under UV light, but they offer a consistency of appearance that some find desirable.

In the end, the choice between a fluorescent diamond and a non-fluorescent one boils down to personal preference. It's a question of whether you appreciate the unexpected glow and potential color-enhancing properties of fluorescence or whether you prefer the stability and predictability of a diamond without fluorescence.

Fluorescence in Diamond Grading

Diamond grading, a process that meticulously evaluates a diamond's quality, certainly takes fluorescence into account. In my quest to understand this further, I delved into the Gemological Institute of America (GIA)'s approach, an esteemed organization that sets industry standards.

GIA’s Fluorescence Study

The GIA has conducted extensive research on fluorescence in diamonds. According to their study, for the average observer, there's no discernible difference between the appearance of diamonds with fluorescence and those without, under normal lighting conditions. They also found that the strong blue fluorescence often has a slight positive effect on the color of lower-grade diamonds, but its impact on high-color diamonds was negligible.

Role of Fluorescence in Diamond Grading by Different Gemological Institutions

In GIA diamond grading, fluorescence is listed as an identifying characteristic rather than a grading factor. It's categorized from "None" to "Very Strong" based on its intensity under UV light. However, other gemological institutions, like AGS (American Gem Society), also consider fluorescence but may weigh it differently in their grading systems.

How Diamond Fluorescence Is Measured and Categorized

Fluorescence is measured by exposing the diamond to long-wave UV light and observing the strength and color of the light emitted. Based on the observation, it's categorized as None, Faint, Medium, Strong, or Very Strong. The color of the fluorescence, most commonly blue, is also noted.

grading fluorescence

Image source: GIA

Does Diamond Fluorescence Affect Value?

Here's where things get interesting. While the GIA's studies suggest fluorescence doesn't significantly impact a diamond's appearance, it can affect its price. Diamonds with strong fluorescence are often priced lower than those with faint fluorescence or no fluorescence, especially in the higher color grades. However, in lower color grades, a medium fluorescence to strong fluorescence can sometimes command a premium due to its potential to improve the apparent color.

To illustrate, here are screenshots showing the prices of diamonds with similar specs but different fluorescence grades.

Prices - No Fluorescence 1.5 ct G VS2

No Fluorescence

Prices - Faint Fluorescence 1.5 ct G VS2

Faint Fluorescence

Prices - Strong Fluorescence 1.5 ct G VS2

Strong Fluorescence

How to Determine if Fluorescence is Right for Your Diamond

Deciding whether fluorescence is right for your diamond is a personal journey that weighs aesthetic preferences, practical considerations, and budget constraints. So, what factors should you consider before choosing a fluorescent diamond?

  • Firstly, consider the diamond's color grade. If you're considering a diamond with a lower color grade (I to M), fluorescence could potentially be a positive attribute, as the blue glow can counteract yellowish tints, making the diamond appear whiter in UV light conditions.
  • Secondly, remember that strong fluorescence can sometimes result in over-blueing, which can make a diamond look hazy or oily in daylight. Although rare, this is a factor to keep in mind if you're considering a diamond with strong or very strong fluorescence.
  • Thirdly, consider your personal aesthetic preferences. Do you find the unique glow of a fluorescent diamond appealing? If so, fluorescence might be a desirable attribute for you.
  • Finally, consider the impact on price. Diamonds with fluorescence often have a lower price-per-carat than similar diamonds without fluorescence. If you're budget-conscious, choosing a fluorescent diamond could be a way to afford a larger stone or a stone with a higher color or clarity grade.

Diamond Fluorescence FAQs

Can I see fluorescence in a diamond with my naked eye?

In regular indoor or outdoor lighting, fluorescence is typically not visible to the naked eye. It's only when the diamond is exposed to UV light (like in sunlight or under a UV lamp) that fluorescence can be observed.

Are fluorescent diamonds considered inferior?

Not at all. Fluorescence is simply another characteristic of a diamond, much like its cut, color, clarity, and carat weight. While the diamond industry generally prices diamonds with strong fluorescence a bit lower, this doesn't mean fluorescent diamonds are inferior. In fact, in certain cases, fluorescence can even enhance a diamond's appearance, especially in diamonds with lower color grades.

Do all diamonds exhibit fluorescence?

No, not all diamonds exhibit fluorescence. According to the GIA, about 25% to 35% of diamonds submitted to them exhibit some degree of fluorescence. However, only 10% show fluorescence that's noticeable to the naked eye under ultraviolet light.

Does fluorescence make hazy diamonds?

No, fluorescence doesn't inherently mean a diamond will appear hazy or milky. Most fluorescent diamonds appear just as clear and brilliant as non-fluorescent ones under normal lighting conditions.

However, in some rare cases, a diamond with very strong fluorescence might exhibit an effect known as "over-blueing" that can cause it to look hazy or oily, particularly in daylight or fluorescent lighting.

Is fluorescence the same in all fluorescent diamonds?

No, the strength and color of fluorescence can vary between diamonds. The most common fluorescence color is blue, but diamonds can also fluoresce in other colors, including yellow, white, and orange. The strength of fluorescence is categorized as None, Faint, Medium, Strong, or Very Strong.

Can fluorescence be created or enhanced artificially?

Fluorescence in diamonds is a natural phenomenon that occurs due to the presence of certain elements (like boron or aluminum) in the diamond's structure. While there are treatments to enhance a diamond's color or clarity, there are no known treatments to enhance or create fluorescence in a diamond.

The Secret Glow

Reflecting on the fascinating journey we've undertaken to explore ]fluorescence in diamonds, I find myself awed by the complexity and beauty of these precious gems. Fluorescent diamonds, with their unique and mesmerizing glow, offer a captivating blend of science, history, and artistry. They challenge our perceptions of value and aesthetics, inviting us to appreciate the wonder of nature and the intricacies of light and color.

In a world where diamonds are revered for their brilliance and sparkle, fluorescence adds another dimension to our understanding and appreciation. As unique as the individuals who wear them, fluorescent diamonds hold a distinct charm that goes beyond the conventional scales of grading and valuation.

So, the next time you find yourself mesmerized by a sparkling diamond, remember that its beauty might not just be skin-deep. Beneath the surface could lie a secret glow, waiting for the right light to reveal its true colors. I hope you'll join me in embracing the fascinating phenomenon of diamond fluorescence, celebrating the diversity and allure of the world's most beloved gemstone.

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