925 Sterling Silver in rose gold plated jewelry facotry Custom Design necklace
You’ve done your research on the 4 Cs and feel like you are ready to jump in and buy the perfect diamond for your partner. But, you notice the stone you’re considering has “strong blue” fluorescence…what does that mean?! Don’t worry! Some people find fluorescence to be intimidating because the best level of fluorescence changes with the color of your diamond. How does one know what’s best? But don’t worry, we will walk you through it so you can be confident in your purchase. Check out our gemologist’s two-step process for choosing the best fluorescence level at the best value below:
What is Fluorescence?
Fluorescence is a diamond’s tendency to emit a soft glow under ultraviolet light (like at the beach, tanning bed, or inside a dance club). The GIA grades diamonds with fluorescence on a scale from “none” to “very strong.” This grading has to do with how intense the glow is under UV light. So, a diamond with no fluorescence will not glow at all, whereas a diamond with very strong fluorescence will glow a lot.
Can you see diamond fluorescence?
Sometimes. Strong and Very Strong fluorescence is visible under strong UV sun or black light. However, less intense fluorescence is often not discernible except to gem experts.
Left: D colored diamond with very strong fluorescence in normal lighting Right: D colored diamond with very strong fluorescence in the sunlight
Fluorescence vs No Fluorescence Diamond
Diamonds with fluorescence look just like diamonds without fluorescence until they are under UV lighting. So, don’t let fluorescence worry you too much. In the instances where you can see fluorescence, it looks different depending upon light source. In other words, a diamond’s glow under the sun is very different than a diamond’s glow under a black light. Under harsh sunlight, diamonds with strong and very strong fluorescence take on a steely blue appearance. Under black light, diamonds with strong and very strong fluor glow like glow sticks!
comparison of various fluorescent diamonds
A GIA grading report showing different levels of fluorescence in normal lighting and UV lighting. Photo credit: Composite photo in UV- Maha DeMaggio/GIA. Composite photo in normal light- Harold and Erica Van Pelt/GIA
What causes fluorescence in diamonds?
Diamonds with fluorescence glow because they have trace amounts of Aluminum, Boron or Nitrogen in them. However, not all diamonds fluoresce! In a study done by GIA researchers, only about 25% to 35% of 26,000 diamonds had any amount of fluorescence when exposed to UV light. In other words, having a diamond with fluorescence is pretty unique!
What colors can diamonds fluoresce?
Blue is the most common color you can expect to see from diamond fluorescence. However, it is also possible for diamonds to have a yellow, pink, or red fluorescence as well. And, the color is not always extreme. It’s really only if you have a stone with strong or very strong fluor, coupled with high UV. For example, when you are outside in the summer (on a day with a 9 or 10 UV index), or under a black light in a nightclub.