Diamond Fluorescence

Diamond Fluorescence refers to the diamonds tendency to emit a soft coloured glow when subjected to ultraviolet light.

Before we get into the details our overall opinion. Fluorescence should not influence your decision to purchase a diamond. Diamond Fluorescence is a hotly debated topic in the diamond industry, but a 1997 study by the GIA suggests fluorescence makes very little difference to the appearance of the diamond.

In the diamond industry, the existence of fluorescence in a diamond (caused by the natural mineral properties of the diamond), has caused many debates and has, in many instances, influenced the pricing of diamonds.


Natural Light


UV Light

Simulated fluorescence

Simulated fluorescence
It is common to find that diamonds with colourless grades (D-E-F) or near colourless grades (G-H-I-J) are lower in price when they exhibit fluorescence.
A GIA study selected a group of similarly graded diamonds with varying degrees of fluorescence to be observed and commented on by study participants. Participants in the study included: trained diamond graders, trade professionals (e.g., jewellers), and average observers (general jewellery buying public).

Here’s a quote from the study:
“For the average observer, meant to represent the jewellery buying public, no systematic effects of fluorescence were detected. Even the experienced observers did not consistently agree on the effects of fluorescence from one stone to the next.

“In general, the results revealed that strongly blue fluorescent diamonds were perceived to have a better colour appearance when viewed table-up [ed: right-side up, as when placed in a setting] with no discernible trend table-down [ed: upside-down]. Most observers saw no relationship between fluorescence and transparency.”
In other words, for the average observer fluorescence made no difference and experienced observers (diamond graders and trade professional) did not agree on the influence of fluorescence. And contrary to previous theories, the experienced/trained observers most consistently determined that diamonds with strong fluorescence were the ones with the best color.

Bottom Line on Fluorescence
Don’t let flourescence unduly influence your choice when selecting a diamond.

If industry experts can’t agree on the influence of flourescence and constantly split hairs over its effect, we feel it falls into the range of minutiae that simply serves to confound and confuse, rather than inform the diamond buying public.

However, because of industry debate and prejudice (which appears unfounded), you may find colourless or near-colourless diamonds that exhibit fluorescence have slightly lower prices than those that do not. Our opinion? Enjoy the better value!!