If you’re diamond shopping, you’ve possibly heard about fluorescence. Diamond expert Dan Moran of Concierge Diamonds explains there is a misconception among consumers that fluorescence is a bad thing. The truth, says Dan, is that it’s a lot more nuanced than that.
Let’s start at the beginning. What is fluorescence? Fluorescence is the reaction of trace minerals within the diamond that cause the diamond to glow—or fluoresce—when exposed to ultraviolet light (like that black light you may have had in your room to make your rock posters glow).
Fluorescence is a greatly misunderstood concept. In the laboratory, special ultraviolet lamps are used to check for fluorescence, but the sun is also a source of ultraviolet rays, so diamonds will react in daylight as well. About one third of all diamonds fluoresce. Of these, the most common color is blue, but diamonds can fluoresce other colors. More than 95 percent of those that do fluoresce will fluoresce blue. The next most common color is yellow. Any other color of fluorescence would be rare.
There are five grades of fluorescence, Dan explains: none, faint, medium, strong and very strong. Let’s review the easy grades first.
If a stone is graded none for fluorescence, he says you don’t have you don’t need to think about this any further. Likewise, if a stone is graded faint for fluorescence, generally that fluorescence will be difficult to detect; it won’t affect the look of the stone is a significant way and in most cases you don’t need to think about it.
Similarly, if a stone has medium, strong or very strong fluorescence, most of the time that will not negatively impact the look of the stone if it is a lower color. Sometimes fluorescence might actually be a good thing in a stone. If a stone is a lower color, the fluorescence can help make the stone look much whiter or brighter, but again, you need to work with a skilled jeweler to assess this as this is not the case in all instances.
Dan suggests you should think carefully about the big picture of the diamond when you’re asking yourself if fluorescence is a good thing or a bad thing.
To sum up Concierge Diamonds’ primer about fluorescence:
None or faint fluorescence, generally nothing to be concerned about.
Strong or very strong fluorescence, generally avoid those stones.
Medium fluorescence in a high-color stone is bad; medium fluorescence in a low-color stone is good.
When you’re buying something as important and intimate as a diamond for an engagement ring, it can be very intimidating. Dan recommends you only buy from a reputable source, and from someone who can help educate you on what to look for and what to avoid.