Diamond Fluorescence
Fluorescence is the tendency of a diamond to emit a (soft) glow when exposed to ultraviolet light (UV light). The fluorescent effect of diamonds is present in over 30% of diamonds and is an important consideration when buying a loose diamond.
When UV light strikes a diamond with fluorescence in diamonds, the stone emits a glow. Most often blue, this glow can also appear in shades of green, yellow, white, or red. Blue fluorescence is the most common.
Fluorescence can occur in different intensities, such as Faint fluorescence, Medium fluorescence, or Very Strong fluorescence.
Gemological laboratories like the GIA rated diamond fluorescence on a scale from "None" to "Very Strong".
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Is Diamond Fluorescence Important?
In a small number of diamonds, the presence of fluorescence creates a hazy, milky, oily, or cloudy appearance. For this reason, diamonds with very strong blue fluorescence can sometimes be valued lower than similar diamonds with Faint or Medium fluorescence.
If you have selected a diamond with strong fluorescence, contact a Diamond Expert to have it visually inspected before purchasing.
Does Diamond Fluorescence Affect Value?
Fluorescence can enhance or detract from the diamond price. The bluish tint from blue fluorescence can improve a lower-color diamond (J-M color rated) by canceling out the yellow tint, resulting in a more colorless appearance.
However, in a very high-color diamond (D-F color rated), diamond fluorescence may have the opposite effect, creating a milky appearance.
It’s estimated that about 30% of diamonds have some degree of fluorescence, so chances are you’ll encounter some of these stones while shopping for a diamond, white or blue.
How Fluorescence Affects the Value of Diamonds
Sometimes, a diamond's level of fluorescence will not affect its price, while at other times, it will. Colorless diamonds (D-F) are sold at a discount if they have a fluorescent effect under UV light because the fluorescence can make them appear slightly oily or hazy.
However, diamonds with a color grade of I-M are sold at a premium due to their blue fluorescence complementing the yellow tint in lower-color diamonds, making them appear whiter and higher in the diamond color range.
GIA's Fluorescence Study
While there are many misinformed opinions on whether fluorescence in diamonds is good or bad, the Gemological Institute of America’s (GIA) in-depth study of diamond fluorescence offers clarity.
"GIA studies show that for the overwhelming majority of diamonds, the strength of fluorescence has no widely noticeable effect on appearance. In the GIA Fluorescence Study, it was found that the average person could not distinguish between a diamond with fluorescence and one without. In many cases, observers even prefer the appearance of diamonds with medium fluorescence. In rare cases, diamonds with very strong fluorescence may appear hazy or oily, though fewer than 0.2% of diamonds submitted to GIA show this effect."
Going Out For The Night?
Frequent nightclubs or raves? Fluorescence is rarely seen unless a diamond is under heavy UV lighting, such as direct sunlight or black lighting.
Take a look underneath and click the "on" and "off" button to view how a diamond will illuminate under UV or black light.
Differentiating Diamonds With & Without Fluorescence
According to a GIA study from 1997, the fluorescence of a diamond does not affect its appearance when looking at it from upside down. However, when the diamond is right side up, the average person may be able to spot a difference in a diamond with a strong or very strong fluorescence.
However, as we mentioned before, the difference is not a bad thing, as the fluorescence may slightly enhance the visible color of a lightly colored diamond.
Diamond Fluorescence FAQs
What causes fluorescence in diamonds?
Certain impurities or structural defects cause fluorescence in diamonds. The most common causes are elements such as nitrogen, boron, and aluminum that become trapped during the diamond’s formation. Fluorescence is found in over 30% of natural diamonds and can also be present in lab-grown diamonds.
Can I identify a fluorescent diamond with the naked eye?
Fluorescence can sometimes be visible to the naked eye, especially in diamonds with strong or very strong fluorescence ratings. These diamonds often glow blue under UV light, such as in direct sunlight or office lighting. In some cases, diamonds with medium or higher diamond fluorescence may appear cloudy or hazy to the naked eye.
Can fluorescence impact the value or price of a diamond?
Fluorescence can impact the price and value of a loose diamond by up to 60% compared to diamonds without fluorescence. That's why many value-conscious buyers look for fluorescence when purchasing a diamond.
Should I avoid purchasing a diamond with fluorescence?
The presence of fluorescence in a diamond is not necessarily a bad thing. In fact, according to a recent study by the GIA (Gemological Institute of America), many observers prefer the appearance of diamonds with medium to strong fluorescence over diamonds with no fluorescence present.
Regardless of fluorescence, inspecting a diamond in person before you finalize your purchase is always advisable.
Does fluorescence affect diamond grading?
In the GIA diamond grading report, fluorescence is not a grading factor like the 4Cs but an identifying characteristic. The report indicates the fluorescence intensity to provide transparency and information to potential buyers.
Should I Buy a Fluorescent Diamond?
The decision to buy a fluorescent diamond depends on your personal preference. The 4Cs - color, cut, clarity, and carat - are more important than fluorescence when choosing the right stone. Some diamond buyers prefer diamonds with fluorescence because it can reduce the price, making high-quality diamonds more affordable.
Be sure to discuss the diamond’s fluorescence with your retailer to make an informed choice.