Friday 07 December 2018

Fluorescence and Color Diamonds

Fluorescence and Color Diamonds


Often times, fluorescence is misunderstood as a negative attribute that compromises the quality of a diamond, but in most of the cases, that is far from the truth. Here are some questions and answers to clarify some murky issues concerning misconceived characteristics of fluorescence.


What is fluorescence in diamonds?

Fluorescence in diamonds refers to a tendency to emit a soft colored glow when subjected to short or long waves of ultraviolet radiation, such as a “black light” (think of how your diamond responds under a bright sun, tanning bed, or at a dance club). And even when the light source is removed, the diamond will continue to fluoresce, but only for few nanoseconds, giving off the illusion that the “glow” has stopped instantly when the light source was removed, unlike phosphorescence, which persists as an afterglow.

Fluorescence in diamond is considered as an identifying characteristic, meaning, additional information that helps to distinguish one diamond from another.  Thus, it has little or no effect on a diamond’s sparkle unlike the cut and clarity criteria. Therefore, it can not weaken the diamond’s structure in any way.

Fluorescence in color diamonds.

The phenomenon of fluorescence is caused by different variations in the atomic structure, and only 30% of colorless diamonds fluoresce, while 60% to 100% of natural color diamonds emits the glow - depending on color and the origin of the stone.  For example, 90% or more of blue diamonds are noted as having no observable fluorescence, but pinks diamond tend to fluoresce more than other diamonds.

Contrary to fluorescence in colourless diamonds - which is mostly blue -  fluorescence in natural color diamonds varies greatly. Blue is the most common fluorescence, but there are white, orange, orange-yellow, yellow, green, and red as well.  

The Aurora Butterfly of Peace.  Photo: R. Weldon. Copyright: GIA.The Aurora Butterfly of Peace - Fluorescence Photo: R. Weldon. Copyright: GIA.

The Aurora Butterfly of Peace. Daylight and under UV light. Photo: R. Weldon. Copyright:GIA.

How is fluorescence graded?

Fluorescence in diamond is considered as an identifying characteristic, not a grading factor like clarity and cut. Therefore, Diamond Grading Reports describe a diamond’s fluorescence by five levels of intensity - None, Faint, Medium, Strong and Very Strong.


Which diamonds fluoresce?

All types of diamonds - natural, synthetic, treated - and also stimulants can emit fluorescence, and the nature of each glow contains vital information for the gemologists to determine whether or not the diamond is synthetic or treated, depending on its response to short and long waves of ultraviolet light. GIA also uses a fluorescence imaging instrument to reveal characteristic growth patterns within crystals.

Fluorescence - GIA

Telltale growth patterns for natural and synthetic diamonds. Photo GIA.

What are the myths around fluorescence?

Fluorescence is generally perceived as an undesirable trait.  And such misconception is far from the truth, as scientific studies and professionals in the field agree that fluorescence is actually a positive characteristic most of the time. And according to HRD Antwerp “even strong fluorescence does not negatively impact a diamond’s appearance.”

Fluorescence is not a negative trait which compromises the value of the natural diamonds, therefore, it shouldn’t be a factor to bring down the price.  As HRD Antwerp points out, “There are no grounds on which to justify the price penalties that currently apply to fluorescent diamonds,” which Alan Bronstein, a trusted advisor of colored diamond and the President of National Colored Diamond Industry Association (NCDIA), echoes - “Argyle pinks have fluorescence and yet it has no influence on their price.”


When does fluorescence have negative effects?

Two factors need to be taken into account: the color and the strength of the fluorescence.  In exceptionally rare cases, the combination of intrinsic color of the diamond and the color and the strength of the fluorescence could possibly create a negative effect.

In a rare case of extremely high level of fluorences, it could affect the clarity and brilliance of the diamond, and the stones could appear milky or hazy to the naked eyes, making it nearly impossible to miss such symptoms.  


As for the unusual case of yellow diamonds with a extremely strong blue fluorescence, the color could appear less “vivid” due to the phenomenon created by the two complementary colors - blue and yellow.

Aside from those atypical cases, GIA Fluorescence Study states that average person could not tell the difference between a diamond with or without fluorescence.  And for the overwhelming majority of diamonds, the strength of fluorescence does not have noticeable effect on appearance at all.


Can fluorescence enhance the beauty your diamond?

The answer is, Yes!  

While fluorescence has no negative impact on the structure and the quality of a diamond, it can enhance the beauty of a diamond.

In the case of yellow diamonds with yellow fluorescence, the color of the stones will appear even more intense, especially when viewed under strong natural light.  This is also true for greenish-yellow color diamonds from Venezuela, as the fluorescence cast unique and fascinating color on them. Orange diamond with orange fluorescence will also appear much more intense and vivid in color

With or without?

Simply put, fluorescence in diamonds should not be considered as a negative trait that devalues the stones.

On the contrary to the general misunderstanding, fluorescence actually plays a positive role by contributing to the uniqueness of natural color diamonds by adding an individualized touch to each color that can not be emulated or duplicated otherwise.

At Langerman we even play with fluorescence and create extraordinary jewels with natural color diamonds that transform in various colors depending on different source of light: daylight - sunlight - ultraviolet light.

Ring under Daylight - sunlight - UV light Fluorescence


The jewels  reflect personal taste. In the end it doesn’t matter if it’s with or without fluorescence.  You just need to fall in love with “the one” that captures your heart.