What is Fluorescence?
There is so much you need to know about diamonds to be able to make a good diamond purchase, buying diamonds can seem like a maze and the amount of endless conflicting information can be overwhelming.
"Fluorescence is the visible light some diamonds emit when they are exposed to invisible ultraviolet (UV) rays. On a GIA diamond grading report, fluorescence refers to the strength, or intensity, of the diamond’s reaction to long-wave UV, which is an essential component of daylight. The light emitted lasts as long as the diamond is exposed to the ultraviolet source." (Diamond Fluorescence | The 4Cs of Diamond Quality by GIA)
Most fluorescence shows blue (just like in the image bellow), it is to my understanding that fluorescence is caused by a presence of a gas at the formation point of the diamond 20-35% of diamonds will exhibit this from faint to very strong blue, applying this to basic color theory that when you over layer yellow with violet/blue you get an optical illusion of white, just like those teeth whitening pens. I know this is a very simplistic way of looking at this phenomenon- however given the correct combination of fluorescence and yellow hues within a diamond you will actually get a diamond that in fact looks whiter than it actually is.
Why is this a good thing? If you are shopping some fluorescence can make your stone look better than it actually is, this is only a good thing if you are informed of this and in fact know you are purchasing a stone with Medium to Very Strong Fluorescence and the stone is in the sweet spots of color between I and M on the yellow color hues only, the cut of the stone is also extremely important as the light return is determined by the cut of the stone.
The brilliancy of a diamond is completely dependent on the precision of how each facet is cut. For optimum light return all the angles and facet sizes need to be in harmony to create a perfect light prism, and you should be able to see a rainbow spectrum within the diamonds as the light bounces back from all the different facets in the diamond like a beautiful choreography.
When did fluorescence become a strong player in the value of a diamond?
About 8 years ago the industry went a bit wild with fluorescence, and since it has become a strong player in determining the value of a diamond typically with stones displaying medium to very strong being less valuable than the counterparts with faint to none.
Here are helpful and informative articles by the GIA which explores a little further about this topic:
Diamond Fluorescence | The 4Cs of Diamond Quality by GIA
Is Diamond Fluorescence Good or Bad? (gia.edu)
Who to trust?
The GIA, who is a non-profit organization specialized in gemology GIA stands for Gemological Institute of America - the provide amazing visuals and information that will equip you to make an informed decision.
Trust your gut! if s deal seems too good to be true, it probably is! and remember cheap diamonds are cheap for a reason, if you need help purchasing or choosing a diamond feel free to ask for help
Diamonds are fascinating topic and there is lots to learn, I hope you have fun doing so.