What Causes Fluorescence in Diamonds?

What is diamond fluorescence? Some people cherish the illuminating glow, others hate it, while a few don’t know or care about fluorescence either way. Yet, it’s a diamond characteristic that can have a slight impact on a diamond’s overall appearance - and a big impact on its value. For this reason, it’s highly recommended that diamond buyers become familiar with fluorescence before making a purchase, if you want to learn more then check out our comprehensive guide to diamond fluorescence.

So what exactly is fluorescence?

When a diamond is exposed to ultraviolet light (nightclub black lights, fluorescent light bulbs or light sunlight), it can sometimes give off a faint glow. This glow or illumination is called fluorescence. The fluorescence effect (being able to see the glow) appears in over one-third of all diamonds and it is not easily detected to a novice or untrained eye.

The glow most commonly appears blue, however diamond fluorescence can also appear in shades of green, red, white, or yellow.

What causes fluorescence in diamonds?

Fluorescence occurs when a diamond contains a trace amount of an element that reacts under UV light. This is why the odds of having a pure colorless diamond is highly unlikely, because diamonds in circulation contain a number of compound elements that have been absorbed over millions of years.

There are three elements that can be absorbed by the diamond that will cause fluorescence:

  • Aluminum
  • Boron
  • Nitrogen

Due to the variances in the levels that diamond fluorescence can glows, the Gemological Institute of America (GIA) has established key identifying characteristics to measure the intensity of the illumination:

What effect does fluorescence have in colorless diamonds?

The effect depends on the color grade of the diamond combined with the characteristics (i.e., none, faint, medium, strong, etc.) and color of the fluorescence. Blue is the most common color of fluorescence seen in colorless diamonds. In a lower grade colorless diamond (J-M color rated) blue fluorescence may compliment the color of the stone, by eliminating the faint yellow appearance. On the other hand, in a higher grade stone (D-F color rated), a yellow fluorescence can have an adverse affect in the clarity causing a cloudy, hazy, milky or oily presentation.

The effect of fluorescence on fancy color diamonds

In fancy color diamonds fluorescence has the potential to help enhance the color of the stone. The color of the diamond paired with the color of the fluorescence can amplify the overall look. For example yellow stones typically have some level of fluorescence present. In some circumstances the presence of fluorescence is not noticeable. While in other cases the characteristics (strong, very strong) of the yellow diamond my have a brownish color tint or a milky presentation.

Can an average person easily notice diamond fluorescence?

According to an in-depth GIA study that observed the effect of blue fluorescence on diamond appearance:

“For the average observer, meant to represent the jewelry buying public, no systematic effects of blue fluorescence on the face-up appearance of the groups of diamonds were detected. Even experienced observers did not consistently agree on the effects of fluorescence from one stone to the next.”

Essentially in most cases, the naked eye was unable to detect fluorescence in diamonds positioned face up.

Is diamond fluorescence good or bad?

The presence of fluorescence in diamonds is a personal preference. The diamond that has the most appeal to your eye is the one that you should go with. Purchasing a diamond is an investment that may be with you for the rest of your life. Your happiness is all that matters. Seek out the advice and knowledge of an expert before purchasing.

Need advice on fluorescence from a Diamond Expert? Call Brilliance.com, 866-737-0754.

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