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Hello there! My name is Shirley and I warmly welcome you to Diamonds-Source.com. I’m a jeweler with more than 5 years of experience and decided to create this website to share my knowledge on diamond buying.

One of the most common question I get asked is the impact of fluorescence on a diamond’s value and appearance. This week, I had written the following article to address this issue and I hope it helps give you a better understanding of it…

vintage diamond earring

Diamond Fluorescence and Their Impact on Fancy Colored Stones

When buying diamonds, most people keep in mind two obvious goals. First, obtaining a stone that has good value – it is excellent when it comes to examining the four characteristics and it is also somewhat unique maybe. Second, with the possible exception of billionaires, people want to get their valorous stones at a price as low as possible.

In the following few paragraphs we will talk about one of the most interesting topics when it comes to gemology – diamond fluorescence in fancy colored stones, a feature that happens to increase uniqueness and apparent beauty while it usually decreases the price tag.

What is diamond fluorescence?

If you have ever attended an introductory physics or chemistry course, you have probably seen that particular crystal lattice of carbons that we call diamonds. It is good to know that in natural circumstances scientifically clear diamonds do not exist, there are always compound elements present.

The amount of these compound elements defines the quality of the diamond in question – in most cases, the less of them, the better. However, in some special cases compound elements can cause preferable results. Usually, the presence of non-carbonic elements causes coloration, thus will the affected diamonds be classified as “fancy colored diamonds”.

However, the presence of nitrogen, boron and/or aluminum causes a coloration that is not usually visible to the naked or untrained eye, at least not under regular sunlight. These elements do not directly affect the main color of the stone, rather, they change the color of the light the exits the stone. This light is only visible under ultraviolet light unless it is very strong.

diamond fluorescence

How does fluorescence manifest itself?

Fluorescence can be observed in the case of colorless diamonds as well, but in the case of these gem stones it only appears with a yellowish or bluish tint. Since in the case of fancy colored diamonds the presence of compound elements is more definite and the light already has to pass a colored substance, fancy colored diamonds have a much broader scale of colors when it comes to fluorescence. So, it is possible to find fancy colored diamonds with fluorescence in shades of pink, green, orange, yellow, blue and even white.

Fun fact: the color of the diamond does not necessarily match the color of the glow.

Since the strength of fluorescence can change the overall appearance of a stone, the GIA decided to differentiate diamonds with different levels of this phenomenon. As a result, there are five different levels ranging from “none” through “medium” to “very strong”. You can see a chart of varying intensities of this effect here.

strong blue fluorescence

Controversial prices of fluorescent diamonds

We are used to the fact that when something is rare, its price is higher. With only 35% of diamonds having any noticeable fluorescence and only 10% of them having enough to change the overall look of the diamond; you would expect these diamonds to be priced highly above their non-fluorescent counterparts.

While some diamonds can benefit from their “special effect”, in many cases the fluorescence does not match the base color of the stone and a bluish glow can make a yellow diamond easily look blurry. All the stones that belong to the latter group are usually priced much lower than they would be without their fluorescence.

While gemologists have their system for pricing these stones, you should definitely take a look at these gorgeous stones since even they might not look like as crystal clear as you would expect from diamonds in general, they are still astonishing pieces.

I hope this article revealed some insights on diamond fluorescence. Feel free to get in touch with me if you have questions…