Fluorescence
Importance and Impact of Fluorescence on a Diamond?
What is fluorescence in a diamond?
Fluorescence is the effect that is seen in some gem-quality diamonds when they are exposed to long-wave ultraviolet light (such as the lighting frequently seen in dance clubs). Under most lighting conditions, this fluorescence is not detectable to the eye. However, if a diamond is naturally fluorescent, it will emit a soft colored glow when held under an ultraviolet lamp. Fluorescence is not dangerous to the diamond or to the wearer; it is a unique and fascinating quality that occurs naturally in a number of gems and minerals.
Do all diamonds fluoresce in the same way?
No. Some diamonds do not fluoresce at all. On diamond grading reports, non-fluorescent diamonds are described as having either “inert” fluorescence or “none.”
Of the diamonds which do exhibit fluorescence, the degree of fluorescence can vary from “faint” (a slight glow of color that is difficult to see under ultraviolet light) to “medium” to “strong” to “very strong” (a deep, even glow that is very evident under ultraviolet light).
Even the color of
the fluorescence itself can vary from diamond to diamond. Blue is the
most common color of
fluorescence which occurs in diamonds, but yellow, green and white are
among the other naturally-occurring colors of fluorescence. In fact, the
famous Hope diamond exhibits a rare, red fluorescence when it is exposed
to ultraviolet light.
Is fluorescence a bad thing in a diamond?
Not at all. Most
of the time, fluorescence doesn’t affect a diamond one bit under normal
lighting conditions.
In the winter of 1997, the GIA published findings on the effect of blue
fluorescence on the appearance of diamonds in their journal, Gems &
Gemology. After studying 1000 diamonds, the conclusion was that for non-trade
observers (that is, the majority of the jewelry-buying public), the difference
between varying levels of fluorescence was indistinguishable. Specifically,
for most consumers, fluorescence had no visible effect on a diamond’s
color appearance or transparency. In the final sentences of the study,
the GIA concluded:
“The present study also challenges the trade perception that fluorescence usually has a negative effect on better-color diamonds. Our results show that the diamond industry would be better served by considering each individual diamond on its own merits.”
In fact, many people happily own diamonds for their entire lifetimes without ever being aware of the presence or absence of fluorescence in their stones. While most people are a little uncomfortable with the idea of fluorescence when they first hear about it, many find it very fascinating and attractive when they have the opportunity to see it in person.
When choosing a diamond with I color or below, strong fluorescence and higher can create an aesthetic advantage for customers. In diamonds with these colors, the color of the strong fluorescence actually counteracts the slight yellow body color of the diamond, creating a diamond that appears to be more white or colorless than it actually is. In this case, budget-conscious consumers can purchase a lower-color but whiter-looking diamond for less than they would pay for a higher-color diamond with a comparable face-up appearance.
Diamonds with no fluorescence or faint fluorescence have no effect on value or appearance. Financially and visually, medium fluorescence has only a slight effect.
In some rare cases,
very strong fluorescence may create a foggy or “oily” appearance that
detracts from the brilliance of the diamond. However, such diamonds account
for only about 2% of all gem-quality diamonds on the market. As mentioned
in the above-referenced GIA study, it is important to judge each diamond
on its own merits.