Diamond Fluorescence is a glowing phenomenon in diamonds that can greatly effect their price. Fluorescence in diamonds is not one of the Four C's, but it is a key factor that has prompted many questions to us. So . . . we will address the subject on this page to provide you with an opportunity to learn about fluorescence in diamonds.
In loose diamonds or mounted diamonds, fluorescence, which refers to the photo-luminescence of a diamond, is caused by trace amounts of the element boron. This fluorescence phenomenon can be observed when the boron in a diamond is stimulated by Ultra-Violet (UV) light.
Fluorescence in diamonds is a factor described on GIA, AGS, and other loose diamond graded certificates. It is classified, or graded, as "None", "Faint", "Medium", "Medium Blue", "Strong", "Strong Blue" or "Intense Blue". Some diamonds will fluoresce in other colors, white and yellow are examples. However, by far, the most common color observed is blue.
The scale below will give you a visual idea of the different Fluorescence Grades and the color degree to which a diamond might glow when stimulated by fluorescent light. Expressed another way, if you are out at night and go into a restaurant or nightclub with fluorescent "black lights" . . . the diamond will glow blue with an intensity approximately equal to the scale below. A jeweler with GIA or AGS credentials will gladly demonstrate this phenomenon for you.
Some people believe that fluorescence in diamonds is a bad thing, but this is not necessarily true. Fluorescence in diamonds can be either bad or good. That's why it is important to know the facts. The best thing about diamond fluorescence is that both its presence and its effect on any diamond you are considering . . . can easily be demonstrated and observed. As noted above, an experienced reputable jeweler will show you exactly how fluorescence effects the diamond. If a jeweler can't or won't demonstrate the effect of fluorescence on any diamond you are considering . . . leave the store.
The presence of fluorescence in diamonds is considered bad when it causes a diamond to appear hazy or oily. This occurs most commonly and the strongest when in natural daylight. The reason is because the boron in the diamond is stimulated by the ultra-violet light waves in natural daylight. If a diamond has fluorescence, it will glow to some degree under a "black light", a fluorescent light. Here, again, the reason is because the boron in the diamond is stimulated by ultra-violet light.
The presence of fluorescence in diamonds is considered good when it enhances the appearance of a diamond. In fact, there are authorities on diamonds who believe fluorescence in diamonds can be considered very positive because, as noted above, it can actually improve their appearance. Faint flourescence can typically have a positive effect on diamonds that are not colorless, those diamonds "G" in color or below. Fluorescence can make some diamonds appear lighter, brighter, and whiter. And, depending on the amount of fluorescence . . . the strong presense of this phenomenon in a diamond can reduce its price. The key is whether or not it effects the diamond's appearance and to what extent it is effected . . . positively or negatively. We actually favor faint to medium fluorescence in diamonds that are not D, E, or F in color. And, it is important to know that faint fluorescence in colorless diamond typically does not have an adverse effect on the stone.
So, how do you as a shopper deal with the subject of diamonds fluorescence? After the salesperson finishes telling you about a particular diamond, if they haven't mentioned or discussed fluorescence . . . ask the question, "Does this diamond have fluorescence?" If the answer is, "Yes" . . . then, you ask, "To what level?"
Then, knowing that fluorescence is present . . . and to what degree, you can decide
whether or not it is effecting the diamond's appearance. And the way you do that is
by examining it under ALL lighting conditions . . . florescent (regular tube lights),
incandescent (regular light bulb), "black light" (ultra-violet), and natural daylight. It is
especially important that you ask to view the diamond next to a window . . . so that you can
see it in direct sunlight. If the diamond does not appear hazy or oily under any of
these lighting conditions, then you can comfortably consider the diamond.
Now that you have learned about diamond fluorescence, if you have also reviewed all 4 "C" pages . . . you now know the key factors considered in describing the size and quality of a diamond, the very same factors used in determining its price or value. With this knowledge you can shop for a diamond and buy it with a reasonable degree of confidence. Ultimately, when considering which diamond to buy, if all factors are the same . . . you buy the one with the best price.
If you have any remaining questions related to Fluorescence in Diamonds, any of the
Four C's, or the Buying Formula, please contact Tom Ross at his office in Atlanta.