The Diamond Pro

7 Awesome Tips on Diamond Fluorescence To Make Her Ring Shine

By Michael Fried

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Bottom Line Recommendation:

If your diamond is H, I, or J color, then look for a diamond with Medium Blue fluorescence like this stone or this stone for an added bonus – it can make your stone look slightly whiter.  If not, your stone will still look great without it.  

If you are buying a diamond with a G or higher color, then find a diamond with either no fluorescence or faint fluorescence.  Otherwise, consider a diamond from the Brian Gavin Blue Collection and shoot for an I or J color stone to get the best value.

These are general guidelines and not every case may fit into these. For guidance on a specific diamond, feel free to contact us.

What is Diamond Fluorescence?

Fluorescence in diamonds refers to how a diamond responds when subjected to ultra-violet light. Ultra-violet light is what makes your whites look whiter, your teeth bright white, and your black-light posters glow.

Some diamonds, when they are exposed to ultra-violet light and other lighting conditions, glow different colors. I’m not going to even try to explain why this is. If you’re interested, google “diamond fluorescence,” and I’m sure you’ll find more than enough information about the science behind the glow.

99% of the time, the glow is blue, but on rare occasions, the diamonds can glow white, yellow, green, or even red in color. The story, however, doesn’t end here.

Strong Blue Fluorescence in Diamonds

diamond_fluorescenceAIf the diamond only glows when exposed to ultra-violet light, then it should naturally only matter if you are someone who spends their days in dark rooms with black light lamps. But the fact is, most diamonds exhibiting Strong Blue Fluorescence appear slightly to severely hazy in regular lighting conditions.
If you’ve done your homework and googled diamond fluorescence, then you might have read about a certain GIA study claiming that even strong blue fluorescence is almost always entirely imperceptible to the average diamond consumer.

Fluorescence in reference to diamonds still remains to be a widely misunderstood concept. When we talk about the fluorescence of a diamond, we are referring to the glow it has when it is exposed to ultra-violet light, and when it exhibits a blue color it appears higher in color than its true body color.

Color Grades

Looking at a diamond color chart, you will find that the GIA will grade the colors of the diamonds on a scale ranging from D through Z. D refers to the colorless diamonds, while Z diamonds exhibit a slight yellowish hue. All diamonds are also considered to contain varying degrees of some kind of color and are then each graded on a different color scale.

Diamonds graded at D are often absolutely colorless and they fall into the highest color grade possible and are also extremely rare. E-F color grades are for colorless diamonds that may contain minimal traces of color that can only be detected by a gemologist. They are also considered rare diamonds.

G-H on the color grade scale refers to near colorless diamonds in which the color may be harder to detect when they are not compared next to other diamonds of higher grades. However, they come at a more affordable price and are an excellent value.

I-J on the color grade scale is set aside for diamonds that have a warmer tone to them but are also considered near colorless.

Finally, K-Z on the color grade scale are diamonds with a noticeable color and are not carried by many retailers.

Reflection, Refraction, and Dispersion for Brilliance and Shine

Diamonds will almost always get their brilliance from three different factors. These factors include reflection, refraction, and dispersion. When light hits a diamond, we are referring to reflection when that light is bounced back after hitting the diamond. The bouncing of light in this manner is what contributes to the shine of the diamond.

When light is reflected, it is typically only a small fraction of the light that bounces, the rest of the light will travel right through the diamond. Refraction is when the light is fractured or gets scattered as the light begins to travel through the diamond and this is where you will see the diamond’s sparkle.

Dispersion occurs when the light first enters through the top of the diamond and then angles itself inside the diamond before it is then aimed back up and through the surface which then creates an almost rainbow-like effect that further contributes to how much the diamond will shine. Refraction and dispersion are also accountable for creating natural light and darker areas in the refracted light. The refraction and dispersion are invaluable when it comes to the overall brilliance of the diamond. The darker areas will become magnified, and there will be contrast. It is this contrast that allows the diamonds to shine as they do.

To sum it up, without reflection, refraction, and dispersion, diamonds would lose their shine and sparkle, and the brilliant shine is what many people are looking for when they choose a diamond ring.

7 Tips on Diamond Fluorescence

  1. It is up to your own tastes to determine if the fluorescence of the diamond is good or bad
  2. Fluorescence can often improve the color of the diamond
  3. Strong blue fluorescence does not necessarily mean there will be a negative effect on the diamond’s overall color and appearance
  4. Faint fluorescence of a diamond can actually save you money without having to miss out on brilliance
  5. When shopping for fluorescent diamonds, always check into the retailer’s return policy- just in case
  6. Buy fluorescent diamonds from a reputable retailer to ensure they’re high-quality
  7. When shopping, it is okay to ask to see the diamonds under UV and normal lighting, as well as inquire about how it may look when exposed to daylight

High Fluorescence Means Hazy Diamonds

I can tell you with absolute certainty, that their research is bunk.  I have seen tens, if not hundreds, of thousands of diamonds in my career and I can tell you without question the following:

  • Strong/Very Strong Blue Fluorescent diamonds usually appear hazy
  • Medium Blue Fluorescent diamonds rarely appear hazy
  • Slight/Faint Blue Fluorescent diamonds never appear hazy

If the diamonds you are looking at have a strong or very strong blue fluorescence, then they will most likely appear hazy, oily, or cloudy and this will also cause the diamonds to appear less transparent. When comparing diamonds back to back, you will definitely see a difference between a diamond with strong fluorescence and one with little or none. It is also important to note that this extreme level of haziness for a fluorescent diamond is also not typical and is not as common as you may think when you are discussing diamonds that are H and lower.

Fluorescence Can Improve Color

Some studies done on fluorescence do make one claim that is correct.  Fluorescence will usually improve the appearance of color in the diamond.

As I suggested in my bottom line recommendation above, if you are buying a diamond with a color H or lower, seek out a diamond with Medium Blue Fluorescence. 

I am hesitant to suggest looking for a diamond with Strong Blue Fluorescence since even lower colors can occasionally look milky and hazy when they have Strong Blue Fluorescence. But the lower you go in color grades, the less likely it will be milky. Here is an example of a beautiful J color diamond  that benefits from the strong fluorescence.

A medium blue fluorescent diamond color can even help counteract any yellowish tint the diamonds may have and can make them appear much whiter. In effect, this will make the diamond color and appearance an entire color grade higher.

Fluorescence can make the diamond shine and sparkle more than a diamond that lacks fluorescent properties.

Hesitations Regarding Fluorescence

I am also hesitant to suggest medium blue fluorescence when purchasing a diamond with very high color (G or better) since on rare occasions even a medium blue fluorescent diamond can exhibit milkiness or haziness when the color is exceptionally high.

If, of course, you are buying a diamond in person and not online, then it’s in your best interest to specifically ask for a diamond with strong blue fluorescence. You are best off asking us about any specific diamond you are looking at. Contact us and we’ll help you out.

It will be more affordable, and since you are there in person, you can see for yourself whether or not the diamond exhibits haziness or milkiness. Make sure to ask to see the diamond in a variety of different lighting settings, if possible.

Brian Gavin’s Blue Line

An interesting alternative if you’re buying online is to consider purchasing a diamond from Brian Gavin’s “Blue” line.  These stones have all been hand-picked by Brian Gavin himself for exhibiting no signs of milkiness or cloudiness. This is where it is apparent that finding a reputable retailer to buy fluorescent diamonds from is crucial when you are looking to obtain a high-quality diamond.

Additionally, the fluorescence improves the diamond’s appearance by making the stone look more colorless without any negative side effects.  The best part is that they’re as brilliant as his “Signature” line of Hearts & Arrows perfectly cut diamonds with one exception – they’re much cheaper. This stunning 1.17ct round diamond is a perfect example where you get a gorgeous diamond that is perfectly cut. Due to the fluorescence, its a bit brighter and cheaper.

We’ve been eagerly recommending these diamonds since early 2012 and everyone that has followed our advice has been extremely pleased.

Buying Locally vs Online

If you’re considering buying locally, despite the savings you might gain by buying a strong blue fluorescent diamond, it will certainly still be cheaper for you to buy your diamond online and purchase either a medium or lower fluorescence.

Unfortunately, however, even James Allen with their advanced photography, cannot show you how the diamond will look face-up in direct sunlight. If possible, it is always better to try and see the diamonds in person so you can get a better outlook on their overall appearance in a different light source.

If you cannot look at the diamonds in person, be sure to check with the retailer about their return policy, just in case. Remember, it is possible to purchase high-quality fluorescent diamonds that boast of the brilliance and shine you are looking for without having to spend a fortune in the process or sacrificing on the overall quality of the diamonds.

About the author
Mike learned the diamond business from the ground-up at Leo Schachter Diamonds - one of the world's top diamond manufacturers. He has been recognized as a diamond industry expert by Time, PeopleMoney, The Daily Mirror, NerdWallet, The Times Herald, Yahoo Finance Australia, The Art of Charm, The Washington Diplomat, The Next Web, and more. See more
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