Learn Everything about Diamond Fluorescence: The Magical Aura of Shimmer in Natural Diamonds
Posted by Hari Krishna
August 10, 2021
Diamond fluorescence is the soft glow visible in the diamond under the Ultra-Violet (UV) spectrum of light. Only 30% of gem-quality natural diamonds show fluorescence of some sort.
Out of those diamonds exhibiting fluorescence under UV light, 99% of them have blue-colored fluorescence. The rest can have green, red, white, yellow, etc., colored fluorescence.
Diamonds show this varied colored fluorescence due to the variation in the standard diamond crystalline structure that possibly occurred during its formation process.
Sometimes, during the natural diamond formation process deep down the earth, some foreign minerals like Nitrogen, Boron, etc., break their crystalline structures and replace the carbon atoms.
If a significant amount of foreign minerals replace the carbon atoms, the diamond becomes naturally colored diamonds.
However, when only a few of them manage to enter the carbon bond, they show a particular colored glow under the UV light.
Because when exposed to UV light, these foreign elements absorb the light energy and excite it later to return to a stable state, and when our eyes perceive that released energy, it shows a distinct glow.
Nevertheless, we must tell you that diamond fluorescence is one of the grading standards measured and mentioned in the diamond quality certification.
Now you must be wondering whether or not the diamond fluorescence affects the appearance of your diamond.
As per the study by GIA in 1997, the diamond fluorescence has no significant effect on the face-up appearance of the diamond.
However, when viewed from the side, the diamond may show some difference in the diamond color if it has a substantial degree of fluorescence.
Well, we will see how the diamond fluorescence affects the diamond’s appearance in this blog. But first, let us start with how the fluorescence in the diamond is graded.
Although diamond fluorescence is visible only under UV light, before 2008, to grade diamond color, the lighting used to be set without considering the UV component. But in 2008, these norms changed.
The diamonds are now graded under the daylight equivalent bulb consisting of a UV component of around 30 microwatts/cm² (which is similar to a bright sunny daylight UV index of 10).
Today, the standard scale of diamond fluorescence grading is None, Faint, Medium, Strong, and Very Strong.
It is to be noted that diamond fluorescence does not majorly affect the visual appearance of diamonds. It is graded just to ensure diamond transparency.
When the diamond shows no excessive glow of any color under the UV light, it receives None fluorescence grading. These diamonds are highly desired and have premium prices.
When a slight to negligible glow is visible in the diamond under UV light, it receives the Faint fluorescence grading. None to faint fluorescent diamonds have almost the same value.
Diamonds with medium fluorescence grading show a light glow of any color under UV light. The medium fluorescent diamonds may lower the diamond prices, depending upon their color.
When a diamond glows intensely under UV light, it receives a Strong fluorescence grade. The strongly fluorescent diamonds adversely affect the diamond color or make them look hazy.
When the diamonds have a bright and intense glow under UV light, they receive the Very Strong fluorescence grading. Theae3 diamonds sometimes look more milky and cloudy.
As said earlier, the diamonds are now graded under normal visual conditions. Hence, the fluorescence effect is already built into the diamond color grade.
Also, the effect of diamond fluorescence on diamond prices varies depending upon the color and clarity. Because higher clarity diamonds may show intense fluorescence.
Though diamonds with none/faint fluorescence are the rarest diamonds, in most cases, the strong diamond fluorescence rarely affects the diamond’s appearance.
However, the colorless diamonds of D-F color grade with Strong and Very Strong fluorescence grade are less desirable for buyers as they might look hazy and milky.
That is the reason why fluorescent colorless diamonds are generally sold at 10-15% lower prices than the colorless diamonds with Faint or None fluorescence grade.
For colorless diamonds, Faint to Medium fluorescent diamonds graded under specialized UV sources is perceptible to buyers.
The fluorescence compliments lower colored diamonds of G-M color grade, as it enhances their whiteness. Sometimes, G-M diamonds with Medium to Very Strong fluorescence have higher prices.
On the other hand, the diamonds with a yellowish tint (color grade N-Z) appear one or two grades up when viewed under UV light.
Hence the fluorescent and near-colorless diamonds have 3-5% higher prices than those with Faint to None fluorescence grade.
As already mentioned, the diamond fluorescence has no visible effect on diamonds, leaving some exceptions (less than 1%) aside where it can affect the diamond appearance positively or negatively.
Hence, we believe that diamond fluorescence should not be the primary factor to consider while buying the diamond. The primary factor will always be 4Cs (cut, color, carat, clarity).
In the end, it all depends on your personal preference of what you find the most attractive in the diamond.
While you are already here, have a look at our latest diamond inventory in 9+ different diamond shapes of 0.18 to 50+ carat in size, FL to I3 quality, whose fluorescence is graded on the standard scale!
