Just what is diamond fluorescence? Have you ever been near a black light while you were wearing a white shirt and noticed that your shirt glowed? Diamonds do something very similar when they are exposed to ultraviolet light. Diamond professionals have not yet come to an ultimate conclusion on whether or not diamond fluorescence is good or bad so what follows is merely our presentation of the facts and our humble opinion.
Diamond flourecence Photo by Harold & Erica Van Pelt
About thirty percent of all diamonds exhibit some fluorescence. Of the diamonds that exhibit fluorescence, 95% give off a blue fluorescence. Some colorlesss diamonds even give off a green, violet, blue, yellow, orange, red or white fluorescence (or a combination), but these colors are more commonly fluoresced by fancy colored diamonds.
Diamond fluorescence is caused by irregularities in the diamond’s atomic structure or the presence of fluorescent elements during the diamond’s formation. These elements include boron and nitrogen, the same elements that can give blue and yellow fancy colored diamonds their color. Learn more about fancy diamonds here and here.
Fluorescence is not a characteristic that is tied to the quality of the diamond. Flawless stones, such the blue hope diamond (featured in the photo above and below, courtesy of the Smithsonian Museum) can have the same fluorescent properties as diamonds of different color and clarity grades.
Florescence and the GIA
The GIA has been educating the public about diamond fluorescence for over 50 years. Older GIA reports mentioned if a diamond had fluorescent properties to help identify the stone; however, in the last few years the mention has evolved into a brief description. The GIA characterizes fluorescence with one of the following terms: None, Faint, Medium, Strong, or Very Strong. If the diamond has a medium fluorescence or higher, the color of fluorescence is also noted the report.
As an authority on diamonds, the GIA conducted a study to determine how common diamond fluorescence is and to see if there was any observable affect on the diamond’s appearance. As a part of the study, the GIA surveyed over 25,000 diamonds. They found that 35% of the diamonds were fluorescent.
As a part of the same study, the GIA assembled several sets of diamonds with similar qualities (in terms of color, clarity, carat and cut) to determine if the quality of the diamond played a role in the diamonds fluorescence. They determined that quality does not matter. Low quality and high quality diamonds can display the same spectrum of fluorescence.
Photo courtesy of the GIA
For the last part of the study, the GIA created different lighting conditions and assembled several groups of people to observe the sets of diamonds. The groups of people included diamond graders certified by the GIA, trained diamond professionals who grade diamonds on a regular basis, another group of professionals that grade diamonds on a semi-regular basis and average observers with limited knowledge of diamond grading practices to represent the general public.
The survey was conducted to determine how a diamond’s fluorescence would affect how its color was perceived by the observers. As such, none of the observers were aware of the diamond’s fluorescence, they were only asked to grade the diamond’s appearance. From this survey, the GIA was able to determine the following:
-None of the people in the ‘general public’ group were able to make a distinction between diamonds with fluorescence and diamonds without fluorescence.
-According to the survey results from the diamond professionals group, diamonds that had a strong fluorescence were thought to have a better color than stones with less fluorescence.
-The greatest effect on improving appearance was most apparent at lower color grades, specifically I and K
-Only 10% of fluorescent diamonds had their appearance significantly improved by said fluorescence. In these cases, observers preferred diamonds with medium to strong fluorescence.
What it comes down to
You will hear different opinions when it comes to diamond fluorescence but you must not deny the above facts.
At Ziva Jewels, we don’t think that diamond fluorescence is as important as other jewelers might make it out to be. We believe that having an excellent color and cut will ensure that you have a beautiful looking diamond. Get more diamond buying advice.
Diamond fluorescence usually decreases the value of a diamond by around 20%. This is due to demand, not because of the diamond’s inferiority. If a seller offers you a discount on a fluorescent diamond, take it; however if they try to charge you more because the blue fluorescence improves the color, do not accept it.
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