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 or "black light." 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 fluorescence 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, their 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, 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 whole lifetimes without ever being aware of the presence or absence of fluorescence in their stones. And 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.
Fluorescence can even be a positive quality in a diamond, and a financial consideration when selecting the diamond that is right for you. Diamonds of high color with strong or higher fluorescence are generally lower-priced than their lower-fluorescent counterparts, due to trade perceptions. Because of this, choosing a diamond with high fluorescence can represent a significant cost-savings for a savvy customer.
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, a budget-conscious consumer 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 diamond 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 every diamond on its own merits. We, at Jewelry Depot, Inc. (JD Houston) have the capabilities and expertise to recognize and select only the finest-quality diamonds.
Jewelry Depot, Inc. (JD Houston) will not sell any loose diamond which exhibits anything less than the highest levels of brilliance.