JEWELRY EDUCATION
Diamond Fluorescence
When in the market for a diamond, one characteristic you may come across is “fluorescence”. Often overlooked and even misunderstood, diamond fluorescence refers to the trait where diamonds emit light when exposed to ultraviolet light – such as the sun, or black light.
According to the GIA, approximately 30% of diamonds showcase some degree of fluorescence. Blue is the typical fluorescence color but yellow, white, green, and even orange are possible.
In this article, we’ll discuss the basics of diamond fluorescence, how it’s graded, and how it affects the look and value of a given stone.
What Exactly is Diamond Fluorescence?
Fluorescence is a diamond’s reaction to UV light. The cause for this lies in the specific trace elements – such as boron or nitrogen – that get trapped within the stone as it’s formed deep within the earth’s crust. These elements, when exposed to UV light, react and activate, causing a glow. This is similar to the minerals that glow under UV light that you may have seen in the past.
While blue is the most common color of fluorescence, some diamonds may fluoresce in white, yellow, or even green. These less common colors are usually considered less desirable, as they can clash with the diamond’s hue, especially if the stone has a yellow tint.
How is Diamond Fluorescence Measured and Graded?
Fluorescence isn’t graded in the traditional sense by the GIA; rather, it’s an identifying characteristic. On GIA grading reports, fluorescence is listed on a scale ranging from None to Very Strong. Understanding these levels can help you gauge how fluorescence might affect your diamond.
- None: No fluorescence when exposed to UV light.
- Faint: A very slight glow – not visible to the naked eye even under UV light.
- Medium: Moderate fluorescence – visible under UV light but with minimal to no effect on the diamond’s appearance in normal light.
- Strong: Noticeable glow under UV light, and can potentially affect the diamond’s appearance in daylight or certain lighting.
- Very Strong: Intense glow that can affect transparency, can potentially make the diamond appear cloudy or hazy in regular light.
Fluorescence is tested under controlled UV light in laboratory conditions. In real life conditions, the presence and intensity of fluorescence may be less noticeable unless the diamond is directly exposed to UV rays – such as a black light.
How Does Fluorescence Affect Appearance?
One key consideration when evaluating fluorescence is how it influences a diamond’s appearance. The effect can vary greatly depending on the intensity and color of the fluorescence and the diamond’s natural color.
In some cases, some jewelers say that fluorescence can enhance a diamond’s appearance. According to this theory, diamonds with lower color grades (I, J, K) may exhibit a yellow tint. If these diamonds fluoresce blue, the idea here is that glow can counterbalance the yellow, making the diamond appear whiter and more attractive in certain light conditions. This can create the impression of a higher color grade.
Counter to this, it’s considered that with higher color grades (D, E, F), fluorescence should be avoided. Under these circumstances, it’s thought that strong or very strong fluorescence in colorless diamonds can result in a milky, cloudy, or oily appearance in daylight. This happens when fluorescence interferes with the diamond’s ability to reflect light, making the stone look dull. It should be noted here that according to the GIA, only about 0.2% of diamonds have this “milky” effect due to fluorescence.
With both these scenarios in mind, the GIA actually states that for the vast majority of diamonds, fluorescence doesn’t have any noticeable effect to the naked eye. Nonetheless, it’s still entirely possible for you to notice a difference in the effects of diamond fluorescence – everyone is different, afterall. The best way for you to discern any effects, positive or negative, is to view the diamond in real life, with a reputable jeweler to guide you along the way.
Does Fluorescence Affect Value?
Fluorescence’s impact on a diamond’s value depends on several factors, including the intensity of the fluorescence and the diamond’s overall characteristics.
Generally speaking diamonds with faint to medium fluorescence see little to no impact on value. In fact, faint fluorescence can be desirable to some buyers, as it was mentioned above, these levels of fluorescence for lower diamond color grades are thought to the stone’s appearance by making it appear whiter.
On the other hand, diamonds with strong or very strong fluorescence, particularly in higher color grades (D-F), may be priced lower than similar diamonds without fluorescence due to the potential for the aforementioned milky or cloudy appearances.
It’s worth noting that the market’s perception of fluorescence has evolved over time. Decades ago, fluorescence was seen as a positive feature that made a diamond unique. However, as grading systems became more standardized, fluorescence—particularly at stronger levels—began to be viewed as a negative trait. Today, it’s neither inherently good nor bad—it simply comes down to personal preference and how it interacts with the diamond’s other qualities.
Additional Considerations for Fluorescent Diamonds
Remember, fluorescence does not affect a diamond’s durability or structure. It is purely an optical trait and has no influence on a diamond’s strength or wearability.
If you’re thinking about buying a diamond with fluorescence, be sure to view it in various lighting conditions before making a decision. Look at the stone under natural sunlight, indoor lighting, under a spotlight, and so forth. This will help you decide whether the fluorescence enhances or detracts from the diamond’s beauty. The thing to remember here is that personal preference is key.
Conclusion: Is Diamond Fluorescence Important to You?
In the end, deciding to buy a diamond with or without fluorescence comes down to personal preference. Some buyers like the idea of a unique glow and others prefer to avoid it.
While fluorescence can influence a diamond’s appearance and value, remember that it’s just one of many characteristics to consider. As it was discussed before, in the vast majority of cases it doesn’t really have any discernable effect on daily appearance. While each factor is important, it’s probably one of the lesser traits to consider on your diamond journey.
Elements such as cut, clarity, carat weight, and overall craftsmanship have a much bigger influence in determining a diamond’s beauty and brilliance.
At Kosmima Fine Jewelry, we’ve been guiding clients through the diamond selection process for over 30 years. Whether you’re interested in having a diamond with fluorescence or prefer a diamond without, our team of experts is here to help. Visit our Boston showroom for a personal consultation, and let us help you find the perfect diamond.
