Diamond Fluorescence

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Expert Guidance

As always, feel free to contact one of our diamond and jewelry experts for individualized assistance with choosing the perfect diamond.

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".

Fluorescence

Diamond fluorescence ratings

Below are the possible ratings that may be applied as a description of a diamond's fluorescence on a diamond report:

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

The Fluorescence Effect

Guidance & Advice

Depending on the color of a diamond, the fluorescence can either enhance or diminish the beauty of a diamond. When in doubt, always ask a gemologist to make sure the diamond fluorescence doesn’t affect the brilliance or sparkle.

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.