Diamond Fluorescence - All You Need to Know

When looking to expand ones diamond collection, people, in general, are looking for the same type of arrangement. The goal is to attain the largest and best quality stone possible for the lowest overall cost.


Many characteristics, such as the 4Cs, play extremely important roles in the quality of the precious stones. However, what many don't consider are the features that are relatively blind to the untrained naked eye. Some of these features may slightly reduce the stones overall value, but because they are not easily seen, they won't significantly decrease the quality of the diamonds themselves.

Diamond Fluorescence is a perfect example of a one of these features. It can slightly help reduce the cost of the diamond, while not necessarily lowering the overall value of the stone. Those with years of professional experience can often distinguish the slight difference in appearance under regular lighting. However, to the untrained eye, diamond fluorescence is not noticeable unless seen under ultra violet lighting.




Fancy Color Diamonds different Fluorescence color


What is Diamond Fluorescence

A pure colorless diamond actually has no compound elements of any kind. Only, to find such a prize is absolutely unheard of. The diamonds found are precious stones created with various compound elements absorbed over millions of years in the making. The different elements included in the composition are precisely what define the type of diamond it is. The additional elements that can be absorbed into the diamonds composition and cause fluorescence are nitrogen, boron, and aluminum.


 Very strong Green Fluorescence

Very Strong Green Fluorescence

 strong White Fluorescence

Strong White Fluorescence


Diamond fluorescence is in essence the inclusion of these elements that cause this magnificent glow. Depending on the stones composition, in Fancy Color Diamonds it can appear in a number of different shades or colors such as blue, yellow, white, orange, green, and pink. In colorless diamonds, fluorescence will generally appear only in a yellow or blue tint.

Since diamond fluorescence can glow at different levels, the GIA developed a grading scale to measure the strength of the illumination.


• None
• Faint
• Medium
• Strong
• Very Strong  


If you don’t have access to an ultra violet lamp to view the diamonds, try using a regular black light to cause the affect.


 Argyle Pink stones with Flouressence

Left to Right:   Faint, Medium Blue, Strong Blue, Very Strong Blue


How it all Began
Diamonds were created millions of years ago, deep below the surface of the earth. Over time, while forming, these stones absorbed trace elements of various other minerals. The elements absorbed into the composition of the stones is what created the magnificent glow known today as diamond fluorescence.


Only about 35% of stones available today actually have diamond fluorescence and only about 10% of those have enough fluorescence to cause a change of appearance under ultraviolet light.

The Affects of Diamond Fluorescence
Now, more than ever, certain compound elements are admired for the effect caused on the precious stones. Many diamond retailers will tell you that diamond fluorescence is known as a negative trait in the industry. As a result, the price of diamonds that contain diamond fluorescence is usually slightly lowered due to the 'reduced' quality of the stone. However, there are two points that must be considered about this truly amazing phenomenon:

• Diamond fluorescence can only be distinguished by the untrained eye under ultra violet lighting. Even a very strong fluorescence will appear extremely faint under direct sunlight.

• Depending on the color of the stone and the color of diamond fluorescence, it can sometimes positively add to the color of the stone.

Diamond fluorescence might be an excellent way to get your hands on a beautiful stone that is a little bit above your price range. As a result of the addition, the cost will most likely be reduced. Depending on the intensity of diamond fluorescence, you might find a little more room to negotiate on the price.

Depending on the type of stone you are looking for, diamond fluorescence can have a different effect on the color. In the following two examples, the diamond fluorescence is specifically what improves the quality of the stone, even though the value will still be slightly lowered.

• Scenario 1:  A colorless diamond with an 'I-J' color grade and a 'Blue' fluorescence.
Under certain lighting, the additional glow can actually help to enhance the color of the stone and make it appear as if it is a higher grade color than the stone actually is.


• Scenario 2: A fancy colored diamond that is a ' Fancy Intense or Fancy Vivid Green Yellow' stone with 'Very Strong Green'  fluorescence.
Under certain lighting, the effect can cause the secondary green to glow, which is a rarer color than the dominant yellow, to shine more intensely and actually improve the color of the stone.


One important point to consider before purchasing a stone is exactly what you plan to do with it. If your plan, for example, is to place more than one diamond on a piece of jewelry, the different fluoresce from each stone might appear as a slight unbalance once put next to one another. However, don't let this stop you from constructing a beautiful piece of jewelry. If it is done right, perhaps with a little professional direction, the outcome can be absolutely magnificent.


 FCD jewelry

Fancy Color diamond Jewelry

How Diamond Fluorescence is Viewed in the Industry
The question of whether diamond fluorescence is a positive or negative trait is actually quite a debated subject. There have been many different opinions on the matter which both argue very true statements.

Whether diamond fluorescence will be considered a positive trait or not, will depend entirely on the color of the diamond and the color of the fluorescence.


Not all diamonds fluoresce, and ones that do can be measured. In general, the price will not be affected if it is a 'Faint' fluorescence and might be affected if it's 'Medium' (depends on the characteristics of the stone itself). However, if there is a 'Strong' or 'Very Strong' presence in the stone, the price will likely be reduced.



Fluorescence lamp

UV Lamp

Colorless Diamonds
The resulting effect of diamond fluorescence depends on the color grade of the stone together with the grade and color of the fluorescence. The most common fluorescence in colorless diamonds is blue. In a lower colorless diamond grade, a blue fluorescence may compliment the color of the stone. However, in a higher grade stone, a yellow fluorescence can negatively affect the clarity by withdrawing from the color or causing a milky or cloudy overcast.

What can be said with some certainty is that diamond fluorescence could, under the right lighting, actually add to lower grade diamonds while taking away from higher grade stones.

Below is a great image of diamond fluorescence in colorless stones. The strength of illumination in the stones shown below, from left to right, are Faint, Medium, Strong, and Very Strong.
Fancy Colored Diamonds
In most fancy colored diamonds, diamond fluorescence won’t significantly reduce the intensity of the stone. The fluorescence glow together with the combination of the diamond color can often complement each other. Under the right lighting, diamond fluorescence can actually help enhance the magic.

Finding a yellow diamond with fluorescence is actually quite common. However, the illumination level is usually quite faint. When purchasing a yellow diamond, be sure to speak with the vendor and ask what type of effect the fluorescence has on the stone. In certain cases it might not be noticeable. In others, it can give the stone a slight brownish tint or even a milky appearance. The benefit is that if the fluorescence is not visible, for a significantly reduced cost you can acquire a stone that looks no different from one without any fluorescence at all.

Pink colored diamonds, on the other hand, are quite difficult to find without fluorescence. In fact, since the addition is so common, especially in Argyle pink diamonds, even a strong grade will generally not negatively impact the value of the stone.

In general, a pure blue diamond will not have any fluorescence at all. In the event that fluorescence is found, which most likely means that the diamond is slightly combined with a greenish overtone, the fluorescence will usually not even be noticeable.

Certain diamond fluorescence are extremely rare and actually considered collector's items, for example, a red fluorescence. Be sure to ask the jeweler for their recommendations on the stones.

Whether positive or negative, to see the affect in reality is breathtaking. Have a look at the image below. Images like this are the reason diamond fluorescence is sometimes referred to as magnificent.


Fancy Color Diamond Fluoresence 


The colors of the diamonds shown are:
From left to right: Fancy Deep Brownish Yellow, Fancy Vivid Yellow Orange, Fancy Vivid Yellow Orange, Fancy Deep Grayish Yellowish Green/Chameleon, Fancy Dark Gray Yellowish Green/Chameleon, Fancy Intense Yellow, Fancy Pink, Fancy Greenish Yellow, Fancy Intense Green Yellow, Fancy Intense Green Yellow.

Most importantly, you should be happy with the diamonds you purchase. Make sure to speak to the retailer you are dealing with and find out all the information upfront. Have a look at the stone under different lighting and always look over the certificate.


Contributor: Benji Margolese


Related diamond articles
What Are the Rarest Diamonds

Aside from exquisite beauty, what makes Fancy Color Diamonds so incredibly...

Read More
How Colored Diamonds Are Made

Where do the natural diamond colors of Yellow, Pink, Blue and others...

Read More
What is Diamond Certification

Established in 1931, the Gemological Institute of America, or GIA,...

Read More
Diamond Color

Diamond color is a Fancy Colored Diamond’s most significant...

Read More
Video Gallery