Diamond Fluorescence and its Affects Price & Appearance

What does fluorescence mean in diamonds? 

Diamond fluorescence refers to pieces which often showcase a milky, blue glow when they are placed under ultraviolet lighting. This can create a haze effect in and around the diamond itself. Fluorescence does not have any impact on the brilliance and fire of the diamond itself; however, it can often make low colour grade diamonds appear colourless. This is due to the contrasting colours of yellow and blue cancelling each other out, minimising any colour at all.

Fluorescence is a very contentious issue in the diamond industry. While many diamond valuers often diagnose fluorescence as something of a negative aspect, and there are many still that are adamant that it does not impact the diamond’s quality. Nonetheless, diamonds that show any level of fluorescence are often accompanied with smaller price tags. This is because, despite the contending theories, fluorescence is regarded as being non-pure.


How are fluorescent diamonds formed?

inThe formation of diamonds, starting from miles below the earth’s surface opens up the stones to possessing many different elements as it is pushed up to the planet’s crust. One of these is boron. If diamonds contain traces of this metal during the crystallisation process, they are more susceptible to this fluorescent phenomenon. The amount of boron present will determine the level to which the stone will fluoresce.

While blue is the most common colour, and stones can show a variety of different shades in UV light, such as orange, yellow, and green. Research has estimated that 50% of all diamonds on the market today will show some form of colour when placed under black light. A further 10% of these will often be so strong, that they will make a massive difference to the colour of the stone itself in regular light conditions.

Effect of Fluorescence on Price

D - FIF - VVS2-10 to -15%-7 to -10%-3 to -7%-1%
VS1 - VS2-6 to -10%-3 to -5%-1 to -2%0%
SI1 - I30 to -3%0 to -1%0%0%
G - HIF - VVS2-7 to -10%-5 to -7%-1 to -3%-1%
VS1 - VS2-3 to -5%-2 to -3%0 to -2%0%
SI1 - I30%0%0%0%
I - MIF - I30 to +2%0 to +2%0 to +2%0%


Fancy Coloured Diamonds

The fluorescence present in diamonds may intensify the fancy colour, but it doesn’t make any difference in fancy colour diamonds under the standard light. The yellow fancy colour diamonds that fluoresce yellow will be more vivid under direct sunlight or ultraviolet light, but most of the yellow diamonds fluoresce blue. The presence of fluorescence in the fancy colour diamond would only intensify the colour of the diamond. That is it.

The diamond fluorescence won’t significantly reduce the intensity of the stone in most of the fancy coloured diamonds. The fluorescence glows along with the diamond colour can usually complement each other. If viewed under the right lighting, diamond fluorescence can surprisingly help enhance the magic of its shine.

Getting a yellow diamond with fluorescence is quite common. However, the illumination level in such diamonds is often quite faint. While buying a yellow colour diamond, make sure to speak with the jeweller and ask what type of effect the fluorescence has on the diamond. In certain cases, it might not be noticeable. In others, it can give the stone a slight brownish tint or even a milky appearance. Here, the profit is that if the fluorescence is not visible, for a slightly reduced cost, a stone that looks no different from one without any fluorescence at all can be easily acquired by you.

The diamonds in Pink colour, on the other hand, are not natural to find without any fluorescence. Since the addition is so common, an even powerful grade will impact the value of the diamond usually negatively.

Generally, a pure blue diamond will miss any fluorescence at all. In rare cases that fluorescence is found, which most likely means that the diamond is slightly combined with a greenish overtone, the fluorescence will usually not even be noticeable.

In certain cases, diamond fluorescence is rare and considered as rare collector’s items, such as red fluorescence. Make sure to ask the jeweller for their recommendations on the diamonds.

History of diamond fluorescence 

Fluorescence as an industry dividing issue was not always the case, however. Before grading certificates became an industry norm in the 20th century, diamonds which showcased a blue-white colour (owing to the fluorescence) were often the most highly sought of all. The prevailing opinion at the time was that diamonds were at their most brilliant when showcasing an “ice” effect - something which fluoro diamonds present emphatically.

Even when diamond certification was becoming more widespread as an indicator of a diamond’s quality, these stones were still quite popular right up until the 1970’s. The term milky D became a sensation as a result. This owed both to describing these unique, haze like stones, and their association with incredibly low prices. As a result, it is not rare to have higher colour grade diamonds marked down in price, due to their fluorescence.

Ultimately and most importantly, you shall be happy and satisfied with the diamonds you buy. Be sure to talk to the jeweller you are dealing with and find out all the information upfront. See the stone under various lightings and always ask for the certificate.

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