Is Diamond Fluorescence a crucial buying factor?

Diamond Fluorescence refers to the mineral’s tendency of emitting a visible coloured luminosity when exposed to concentrated ultraviolet (UV) light. With buyers becoming increasingly aware about the many determinants of a diamond’s quality, fluorescence has come under the spotlight for its interesting role in enhancing a diamond’s appearance.

Though presence of slight to moderate fluorescence is acceptable, as it does not actually impact the overall sparkling appearance of the diamond, too much fluorescence can kill a diamond’s colourless beauty to create an undesirable clouded blurring effect that ultimately fails to reflect light efficiently. Whether you are buying diamond jewellery or any bespoke jewellery incorporating one or more diamonds, evaluating its fluorescence component is a sound buying decision.

The GIA Fluorescence Scale

GIA has rated fluorescence in a diamond on a scale ranging from ‘Very Strong’ to ‘None’. The impact of fluorescence on the value of a diamond depends on the intensity of fluorescence, the clarity as well as the colour of diamonds. Fluorescence and colour are crucial in determining the retail value of a diamond.

• Very Strong and Strong: Presence of noticeably strong fluorescence in a diamond leads to a significant colour influence.

• Medium: Existence of average fluorescence leaves a smaller colour influence.

• Faint: Presence of slight or weak fluorescence that does not leave any substantial influence on the overall colour of a diamond. The comprehensive colour is barely perceptible.

• None: Negligible or no fluorescence leaving no influence on the diamond’s colour.

Fluorescence affecting the price of a diamond

The issue of fluorescence has progressively grown to be a point of discussion among the experts. The sub-microscopic fluorescent structures within a diamond emits this common blue colour. In most diamond quality reports authorised by grading laboratories fluorescence is highlighted as a distinguishing characteristic and not as an evaluating component. 

When viewed with incandescent light, all the diamonds in these earrings appear to be the same colour. Photo: GIA

When viewed with a UV lamp, the diamonds in the earrings show different degrees of fluorescence. Photo: GIA

However, the fluorescence factor in a grading report has been used to ascertain the final price of a diamond. The presence of Strong to Very Strong fluorescence can be deciphered in diamonds from the table up perspective.

The common perception of fluorescence negatively affecting the price of a diamond is validated by the price variation observed in diamonds with fluorescence. Approximately 30% of all retail diamonds display fluorescence to a certain degree.

Fluorescent or not, this 1.42 carat (ct) diamond engagement ring, with diamonds lining the band, captivates with its bold, clean lines. Courtesy: 1stdibs.com via GIA.com

Fluorescence in colourless diamonds of D to F categories will lead to as much as 15% price discount as fluorescence is considered an imperfection. The colour compromise resulting from Faint to Medium presence of fluorescence can only be perceived by a gemologist only under UV light.

Is Fluorescence ever good?

Since diamond fluorescence tends to be blue, a complementary shade to yellow, it can positively contribute in making I-M diamonds appear a grade whiter. Thanks to this phenomenon, I-M diamonds possessing anything between Medium and Very Strong fluorescence demand a moderate price premium.

Lower colours appear a tad whiter owing to the existence of noticeable fluorescence. Nevertheless, fluorescent diamonds generally fetch a lower price and diamonds with an invisible glow deliver better value for money.

Historically, a diamond with strong fluorescence has seen its price being marked down when compared to its non-fluorescent equivalent.

For help in choosing a beautifully symmetrical diamond, contact our team on +65 6733 4100 to make an appointment. Our atelier at #05-04 International Building, 360 Orchard Road, Singapore 238869, is now open by appointment. We are also able to take virtual appointments if you aren’t able to come in.