Diamond Fluorescence: 2 Steps to Make it WORK FOR YOU

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.

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!

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.  

Fun Fact: The famous blue Hope Diamond actually fluoresces cherry red!

Is fluorescence in a diamond good?

GIA says it is neither good nor bad. Our gemologist uses it as a tool to benefit color and price! Some people purposely buy a diamond that has fluorescence because they think it is cool. On the other hand, some people are strongly against a diamond with fluorescence because they want the whitest, “purest” stone possible. Then again, others have never heard of fluorescence and have no opinion. So, in reality, it is truly personal preference.

What is the best fluorescence in a diamond?

Fluorescence gets a bad rap, but it shouldn’t. Here’s our gemologist’s two step method for choosing a fluorescence level that looks great and offers great value:

step 1. Make sure it doesn’t cause haze or milkiness

Strong fluorescence causes “milkiness” or “haziness” in a small number of stones. However, contrary to popular belief – this does not occur in the vast majority of diamonds with strong or very strong fluorescence! The problem is, milkiness and haziness are not listed on GIA certificates (I know, crazy, right?) So, it’s very important to confirm lack of haziness or cloudiness with your jeweler. Notably, not all jewelers filter these stones out from their website, or teach their staff to properly identify it. As a result, make sure you ask your jeweler if they’ve checked your diamond, and that they know what they’re talking about!

Gemologist’s Note: Since haziness and milkiness are not desired qualities, Do Amore filters out these stones so our customers never even see them. Therefore, you can rest assured when searching the diamonds on our website, because they have already been checked by a gemologist and are free of milkiness or haziness!

step 2. Choose your level of fluorescence based upon your color grade

If you are choosing a white diamond, go with blue fluorescence (or none at all). Then, choose the intensity of your fluorescence by color grade. Because blue fluorescence is…well, blue…it will cancel out the increasingly yellow tones in near colorless gems. In other words:

If your diamond is colorless (DEF)

Choose none or faint if you want an ice white stone. Our gemologist’s personal opinion is that medium will look just fine, too. Choose strong or very strong if you want a blue glow. (Fun fact! These colorless stones with strong blue fluorescence were called “blue-whites” prior to 1938 when the FTC stopped allowing the term for fear consumers would think they were blue diamonds.)

If your diamond is G or H color

You can choose a medium or even a strong to get max value! No need to pay the “none” premium – your diamond’s very slight tint will get evened out by the fluor! Strong fluor will still show in these stones, however, as they are very white!

If your diamond is I or J color (or warmer)

Choose strong or very strong to get the max benefit of whitening and value! Strong and very strong fluorescence will both save you money and brighten your diamond up. However, as fluorescence is only a glow, and also only visible under certain lighting, unfortunately you cannot expect it to make your I or J color diamond look colorless.

If you are buying a colored diamond

Unless you are buying a warm-colored diamond (yellow, orange, pink, red), do not choose a diamond with yellow fluorescence. Yellow fluorescence as a higher incidence of resulting in haziness and can make a stone appear oily.

Does fluorescence affect diamond value?

Selecting a diamond with fluorescence is a good way to save a little money on a stone with great specifications. As you may already know, an excellent cut diamond that is colorless (D, E or F) and has a high clarity grade will typically be on the pricier side. However, if you take these same specifications and find a diamond that also has strong fluorescence, you can save quite a bit of money. In addition, a warmer colored stone (I or J) that has strong blue fluorescence can give the illusion that a stone is whiter than it is. It is easier to save a drastic amount of money on colorless stones. However, the warmer you go on the color scale, the less amount of money you save. 

Do lab grown diamonds have fluorescence?

Not typically. Because lab grown diamonds are typically Type II, they have less trace elements (remember all that Aluminum, Boron, etc. from above?) to create fluorescence. So, most lab diamonds are graded “none.”

Gemologist’s fun fact: In the one lab diamond we’ve seen to possess fluorescence, it was listed as part of the color grade (bringing to mind the “blue-white” controversy above).

Should You Buy a Diamond with Fluorescence?

If you want a whiter, less expensive near colorless diamond, yes! Diamonds with fluorescence are a unique choice that offers value and quality without having to give up other great specifications in a center stone. Ultimately, though, it is up to you! If you are looking to save a little money while still getting a beautiful diamond, choosing a stone with some fluorescence could be a great option for you! Remember, the most important aspects to consider when buying a diamond are (in order of importance) the 4Cs: Cut, Carat, Color, and Clarity! And, fluor can be a great tool to maximize carat and color. To recap, here are some pros and cons about fluorescence:

Can you help me choose the best fluorescence?

Absolutely! Send us a note here, or email us at care@doamore.com, and we can answer all of your fluorescence questions and choose a great stone for you. Feel free to ask for our gemologist, Corinne, too. She’d be happy to answer all of your most technical diamond questions – fluorescence and all!