Diamond Fluorescence: What is It and Should it Be Avoided?


At Diamond Lighthouse, we want to make diamond experts out of everyone considering selling their diamonds with us. Over at our Diamond University, we talk a lot about the four Cs as being the four main factors that determine the appearance, quality and value of your diamond. There is, however, another factor that can affect the appearance of a diamond just as much as any of the four Cs, but isn’t talked about nearly as much: fluorescence. There’s a lot of conflicting information out there about the fluorescence of a diamond and many jewelers still have misconceptions about what fluorescence really means. We want to fix that. Whether you’re buying, selling or upgrading a diamond, it’s important that you know exactly what you’re dealing with.


What is Fluorescence?

In the diamond world, fluorescence is the term used to describe how the diamond reacts to ultraviolet light. Specifically, how much the diamond glows when you shine UV light on it. The Gemological Institute of America grades fluorescence on a scale of strength from “None” to “Very Strong.” A diamond with “Strong” or “Very Strong” fluorescence will glow much brighter in UV light than a diamond rated “None.” You can’t see diamond flourescence with the naked eye, but in some cases, it can affect how your diamond looks in natural light and even improve a diamond’s color appearance. So now you know what fluorescence is, but how does it affect the perceived quality and price of your diamond? The answer, according to the GIA, is that it shouldn’t, but that hasn’t stopped the spread of some serious misconceptions regarding diamond fluorescence.


Misconceptions About Fluorescence

Though nearly all this “advice” has been thoroughly debunked, there are a lot of people out there, even some who work in the diamond industry and should know better, who are still operating under the same misconceptions: Strong fluorescence is bad, no fluorescence is best, but faint or medium fluorescence is OK in diamonds of lower color quality because it makes the diamond appear whiter. It turns out, according to a GIA study in 1997, that none of this “advice” holds up.

Where did these misguided ideas start? The misconception that fluorescence is something to be avoided goes back to the 1970s. Some folks in the diamond industry saw a correlation between gems that appeared hazy and gems that had a strong blue fluorescence. That led to highly fluorescent gems being sold at lower prices because they were perceived to be of lower quality. That perception spread to the buying public and it became common knowledge that fluorescence was to be avoided. Once Rapaport, maker of the diamond industry’s wholesale price list, started listing diamonds with strong fluorescence at lower prices, the misinformation basically became fact.


The Truth About Fluorescence

In most cases, fluorescence doesn’t make one bit of difference. Sometimes, a strong fluorescence can even be a good thing. In their 1997 study, the GIA found that the average person shopping for diamond jewelry can’t tell the difference between diamonds that have no fluorescence and those that do. When the same diamonds were shown to experts working in the diamond industry, the results were even more surprising. The strength of a diamond’s fluorescence had no effect on the color appearance or perceived value in most cases. In fact, diamonds with strong or very strong fluorescence had better color appearance than low-fluorescence diamonds. Strong fluorescence can actually make a diamond appear to sparkle brighter in sunlight. As for those cloudy, hazy diamonds? The GIA found that less than 0.2 percent of fluorescent diamonds exhibited that effect.

Should You Buy a Fluorescent Diamond?

That’s completely up to you. If you like the way a strongly fluorescent diamond looks, go for it. Don’t be scared off by misconceptions regarding fluorescence. If the jeweler you’re buying from is operating under the old misconceptions and offering the diamond at a lower price, it could end up being a great deal. All that really matters is how the diamond looks on you. Also, it’s important to keep in mind that there are so many more factors that affect the appearance of your diamond, cut being the most important. Visit Diamond University for more information on the four Cs and how they affect the appearance and potential value of your diamond.


If you’re looking to sell a diamond, don’t let all these perceived notions towards fluorescence discourage you. While there are some jewelers who still believe fluorescence is a negative thing, these misconceptions are dying, especially among experts in the industry. Even most jewelers today don’t take fluorescence into consideration when determining a diamond’s price. If one jeweler tries to offer you a lower amount based on your diamond’s fluorescence, take it to someone who knows what they’re talking about.  Sell your unwanted diamonds with the most transparent online diamond brokerage firm operating today: Diamond Lighthouse.


To make sure you get the most cash when you sell your diamond, contact Diamond Lighthouse. Our expert gemologists will valuate your diamond, including an accurate description of its fluorescence, so we can push for the best price. With over 30 years of experience in the diamond industry, we’ve been able to build an exclusive network of expert diamond buyers and dealers that the general public doesn’t regularly have access to. These are buyers who only deal with people in the diamond industry. They recognize that fluorescence doesn’t hurt a diamond’s value and in some cases, actually enhances it. Sell your diamonds with Diamond Lighthouse and we’ll use every tool and angle at our disposal to get you more money.  When you sell diamond jewelry online with the diamond marketplace experts, you’ll feel good in any light.

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