Diamonds Update

Fluorescence in diamonds is a form of illumination created when a diamond is exposed to Ultraviolet (UV) light.  Exposure to UL light can occur from the "backlights" often found in nightclubs, the drying lights used in nail salons, fluorescent lights or direct sunlight. Diamonds emit light due to fluorescence when small amounts of the elements nitrogen or boron are present in the stone. Blue is the most common color of fluorescence, but other colors (yellow, greenish blue, green, white and pink) are also possible.

About 35% of gem quality diamonds have fluorescence visible under an ultraviolet light. About 10% of gem quality diamonds have enough fluorescence to make a noticeable difference in the diamond's color when viewed under incandescent light (low in UL) and in sunlight or fluorescent light (high in UL). In less than 2% (some estimates are as low as 0.2%) of diamonds, the level of fluorescence is high enough to cause the diamond to appear foggy or milky in appearance.

After years of debate and controversy, the diamond industry is still not clear on the visual and financial impact of fluorescence in diamonds.  In the early days of the diamond industry, diamond merchants and consumers valued diamonds with fluorescence because they felt fluorescence improved the color appearance (whiter looking) under lighting with UL components.

In the early 1970’s inflation was soaring and speculators purchased high-color, high-clarity diamonds as investments.  The perceptions of fluorescence took a dramatic turn in the late 1970s when diamond prices were at crazed levels and the speculators attempted to sell their diamonds.  Suddenly they discovered that many of the diamonds they had purchased had very high levels of fluorescence and that when they went to sell their diamonds, stones with higher fluorescence sold for lower dollars.  This shocking revelation spread through the media and the public got its first education about fluorescence in diamonds.

The diamond industry had another fluorescence shock in the 1980s was Russian diamonds were pouring on the market.  These diamonds seemed to have a higher percentage of Medium to Strong fluorescence than had been seen from traditional African sources.  This influx of fluorescence diamonds fueled the debate over fluorescence and created increasingly negative perceptions within the diamond industry.

In 1993, a television “expose” in South Korea (We Want to Know That) aired the negative image of fluorescence in diamonds and brought it to the attention of consumers.

The consumers negative view of fluorescence was quantified in 1997 when the Rapaport Diamond Report (diamond industry’s pricing Bible), indicated that higher-color (D-H) diamonds with Very Strong Fluorescence were selling for 15% less than comparable diamonds without fluorescence.  The perceptions became reality.

The GIA conducted a scientific study in 1997 to better understand the effect of blue fluorescence on the appearance of diamonds.  The study concluded:

1) Observers who were not in the diamond trade could not see any meaningful difference in diamond color or transparency between diamonds with fluorescence and those without.
2) Observers in the diamond industry found not visible difference due to the strength of fluorescence when the diamonds were viewed table-down, as is typical for color grading.
3) Observers in the diamond industry found that diamonds with higher levels of fluorescence had better color appearance (whiter) than diamonds with lower fluorescence levels when view in the table-up position, which is how diamonds are viewed by consumers.

Even though the scientific study indicated that consumer could not see the difference, the introduction of online diamond information at the end of the 1990s meant that consumers were now looking at certifications for information about a diamond rather than relying on the work of the jeweler and their eyes.  The fact that Fluorescence was an easy to understand specification on the grading report, made it easier for consumers to select diamonds based on fluorescence levels.  Even novice diamond shoppers quickly determined that if they wanted their diamond “pure” and free from imperfections, no fluorescence was better than Faint and it was best to avoid the Strong and Very Strong levels.

Over the years, it has become more difficult for retailers to sell diamonds with higher levels of fluorescence.  Even with prices significantly discounted, supplies were greater than consumption.  De Beers’ sightholders are required to accept all the rough diamond in their allotment and a certain proportion of those have stronger fluorescence.  The diamond cutters can choose what shape to cut out of the rough crystal, the size of finished gem and the quality of the proportions for the gem and to some extent the clarity by cutting away from inclusions.  However, they cannot change the color of the stone or its fluorescence.  The cutters must pass on the fluorescent diamonds to the wholesalers and retailers who then must attempt to get the consumer to buy them. 

The diamond industry now has a glut of fluorescent diamond on the wholesale market and on the retail shelves.  Consumers are becoming increasingly wary of purchasing diamonds with high levels of fluorescence so the pipeline is getting full of them.

Because the sourcing of fluorescence diamonds continues, the diamond industry has two recourses: 1) they can reduce prices to entice consumers, but this strengthens the perception that fluorescence is a negative and could result in a bigger glut, or 2) change the consumer’s perception of fluorescence. 

There seems little organized effort by the diamond industry to change the direction of the consumer’s negative perception of fluorescence.  With increasing knowledge, the consumer seems to be more discerning in their diamond shopping with respect to cut parameters, color, clarity, finish grades, and certainly fluorescence.  Time will only tell how the diamond industry will react to the glut of fluorescence that bloats inventories, raises inventory costs, and increases the financial strain of an industry already reeling from high interest rates and squeezed profit margins.