Diamond Fluorescence

Fluorescence, the effect ultraviolet (UV) light has on a diamond, is an important consideration when selecting a diamond. When UV light strikes a diamond with fluorescent properties, the stone emits a glow that is usually blue, but can also be shades of green, yellow, white, pink, orange, and red. The sources of fluorescence, boron and nitrogen, are the same mineral properties that lend to diamond color.

Fluorescence can occur in different intensities. Gemological laboratories rate the fluorescence of each diamond on a scale from "None" to "Very Strong". (Want to speak with a diamond expert? Call 866-737-0754 for expert advice on fluorescence.)

Diamond Fluorescence
None, Nil, Negligible
No fluorescence, no influence on color.
Faint, Slight
Weak fluorescence, not a significant influence on color (barely perceptible).
Medium
Average fluorescence, small influence.
Strong, Extremely Strong
Strong influence, substantial color influence.

Is Fluorescence in a Diamond Good?

Fluorescence can enhance or detract from the beauty of a diamond. The bluish tint can improve a lower-color diamond (J-M color rated) by cancelling out the faint yellow, resulting in a colorless appearance. However, in a very high-color diamond (D-F color rated), fluorescence may have the opposite effect.

In a small number of diamonds, the presence of strong fluorescence creates a hazy, milky, oily, or cloudy appearance. For this reason, very fluorescent diamonds can be valued lower than similar diamonds with fluorescent ratings of "None," "Faint," or "Medium." If you have selected a diamond with "Strong" or "Very Strong" fluorescence, please contact a Brilliance diamond and jewelry expert to have it visually inspected before purchasing

While there are many false and misinformed opinions on whether the presence of fluorescence in a loose diamond is good or bad, it's best to consider the GIA's in-depth, long-running, scientific study of fluorescence:

"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 make a distinction between a diamond with fluorescence and a diamond without. In many instances, observers prefer the appearance of diamonds that have medium to strong fluorescence. In rare cases, some diamonds with extremely strong fluorescence may appear hazy or oily; fewer than 0.2% of the fluorescent diamonds submitted to GIA exhibit this effect."

Guidance & Advice: Diamond Fluorescence

Depending on the color and type of inclusions in a diamond, fluorescence can either enhance or diminish the beauty of a diamond. When in doubt, always ask a Gemologist to make sure the fluorescence doesn’t affect or impact the brilliance or sparkle of the diamond you are buying.

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