The Skinny on Diamond Fluorescence

Fluorescence can seem to be an intimidating subject when choosing a diamond, however armed with the correct knowledge it becomes clear that it's just another factor that needs to be taken into account and is ultimately owing to personal preference and budget.

What is Fluorescence?

In technical terms, fluorescence is the tiny particles in a diamond which most typically emit a blue light, when placed under UV lighting.

As graded by GIA, the fluorescence of a diamond is measured on a scale from None (no fluorescence), Faint, Medium, Strong and Very Strong. The strength of fluorescence in a diamond is not directly correlated to the colour or clarity of the diamond, meaning that the colour and clarity have no influence on the whether the diamond will have fluorescence or not. Diamonds of different colours and clarities can have exactly the same level of fluorescence.

How does fluorescence affect the appearance of a diamond?

Under ‘normal’ lighting conditions there is no visible difference to the naked eye if a diamond possesses either None or Faint fluorescence. Under UV lighting a diamond will emit a small blue glow if it possesses Faint or Medium fluorescence, however, there will still be no effect under normal lighting conditions. In some cases, diamonds that have been assessed to have Strong or Very Strong fluorescence can appear to make the diamond look milky or cloudy. This would have an impact on the beauty and sparkle of the diamond, which is why it is not as recommended as a diamond with lower strengths or no fluorescence at all.  However, each case of fluorescence should be treated individually as sometimes the affects do not necessarily have a negative effect of the diamond. Diamonds of a lower colour (I, J, K, L for example) which possess fluorescence can appear to be ‘whiter’ and more colourless.

It is important to consider the influence that fluorescence has on the price of diamonds. A diamond with faint or medium fluorescence may be priced cheaper, as technically they are regarded as not as ‘pure’ as a diamond without fluorescence. However, in terms of value, if this has no visible affect on the appearance of the item then it may be a better choice in terms of value for money.

The influence of fluorescence

After many years of being a highly deliberated subject, professionals in the diamond industry are still split in their opinion of the positives and negatives of fluorescence.  Our resident Diamond expert gives his opinion on the matter;

“Whilst the commercial image of fluorescent diamonds has taken a blow since the 70's, my personal opinion is that fluorescent diamonds are currently under-valued, and can, most of the time, bring more positives than negatives to a diamond. Of course, one needs to be aware that the more fluorescence there is in a diamond, the bigger the chance the diamond will be milky. Nevertheless, even for strong fluorescent diamonds, that chance is still remote”.