Diamond Fluorescence

The amount of luminosity emitted by a diamond Diamond Tips

- For a less expensive diamond that only sacrifices a little on diamond color – look for a diamond weak or medium fluorescence.

- When money is not an issue, the best diamonds have no fluorescence.

Diamond Fluorescence: The Finer Factors That Make A Great Diamond.

About 1/3 of diamonds have fluorescence, which is the innate ability of a diamond to transfer an invisible light, such as ultraviolet light, into a visible wavelength. The best way to detect the visible effects of diamond fluorescence is under specific ultraviolet light.

Diamonds Viewed Under Ultraviolet Light Diamond Fluroscence Side view
Side View - 1. Very Strong Fluorescence to 5. No Fluorescence


Diamond Fluroscence Top view

Top View - 1. Very Strong Fluorescence to 5. No Fluorescence

There is a whole science on diamond fluorescence – basically in a nutshell: a strong or very strong fluorescence grade can enhance a near colorless grade of diamond to look even whiter under natural light. However, in some instances, a diamond with very strong fluorescence can lend the diamond a slightly hazy or oily appearance, which can have a negative effect on the price of a diamond.


Approximate % Price Change From Non-Fluorescent Diamonds*
Color
Blue Fluorescence
IF-VVS
VS
SI-I3
D, E
Very Strong
-10% to -15%
-6% to -10%
0 to -3%
Strong
-7% to -10%
-3% to -5%
0 to -1%
Medium
-3% to -7%
-1% to 2%
0
Weak
0
0
0
F, G, H
Very Strong
-7% to -10%
-3% to -5%
0
Strong
-5% to -7%
-2% to -3%
0
Medium
-1% to -3%
0 to -2%
0
Weak
0
0
0
I, J, K
Very Strong
0 to 3%
0 to 3%
0 to 3%
Strong
0 to 2%
0 to 2%
0 to 3%
Medium
0 to 2%
0 to 2%
0 to 2%
Weak
0
0
0

* Adapted from Martin Rapport, “Price Indications for Blue Fluorescence Diamonds” 1998.
Some customers may seek this characteristic, and others may avoid it. In our experience, most people choose a slightly to moderately fluorescent diamond over a stone with no fluorescence, with the added feature that it may cost slightly less.

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