Bottom Line Recommendation: If your diamond is H, I, or J color, then look for a diamond with Medium Blue fluorescence for an added bonus – it can make your stone look slightly whiter. If not, your stone will still look great without it. If you are buying a diamond with a G or higher color, then find a diamond with either no fluorescence or faint fluorescence. Otherwise, consider a diamond from the Brian Gavin Blue Collection and shoot for an I or J color stone to get the best value.
Fluorescence refers to how a diamond responds when subjected to ultra-violet light. UV light is what makes your whites look whiter, your teeth bright white, and your black-light posters glow. Some diamonds, when they are exposed to UV light, glow different colors. I’m not going to even try to explain why this is. If you’re interested, google “diamond fluorescence”, and I’m sure you’ll find more than enough information about the science behind the glow. 99% of the time, the glow is blue in color, but on rare occasions, the diamonds can glow white, yellow, green, or even red in color.
The story, however, doesn’t end here. After all, if the diamond only glows when exposed to UV light, it should naturally only matter if you are someone who spends their days in dark rooms with black-light lamps (dance clubs, rides at Disney World, etc). But the fact is, most diamonds exhibiting Strong Blue Fluorescence appear slightly to severely hazy in regular light.
If you’ve done your homework and googled diamond fluorescence, then you might have read about a certain GIA study claiming that even strong blue fluorescence is almost always entirely imperceptible to the average diamond consumer.
I can tell you with absolute certainty, that their research is bunk. I have seen tens, if not hundreds, of thousands of diamonds in my career and I can tell you without question the following:
The study, though, does make one claim that is correct. Fluorescence will usually improve the appearance of color in the diamond. So as I suggested in my bottom line recommendation above, if you are buying a diamond with a color H or lower, seek out a diamond with Medium Blue Fluorescence. I am hesitant to suggest looking for a diamond with Strong Blue Fluorescence, since even lower colors can occasionally look milky and hazy when they have Strong Blue Fluorescence. I am also hesitant to suggest Medium Blue Fluorescence when purchasing a diamond with a very high color (G or better), since on rare occasions even a Medium Blue Fluorescent diamond can exhibit milkiness or haziness when the color is exceptionally high. If, of course, you are buying a diamond in person and not online, then it’s in your best interest to specifically ask for a diamond with Strong Blue Fluorescence. It will be cheaper and since you are there in person, you can see for yourself whether or not the diamond exhibits haziness or milkiness.
An interesting alternative if you’re buying online is to consider purchasing a diamond from Brian Gavin’s “Blue” line. These stones have all been hand-picked by Brian Gavin himself for exhibiting no signs of milkiness or cloudiness. The fluorescence improves the diamond’s appearance by making the stone look more colorless without any negative side effects. The best part is that they’re as brilliant as his “Signature” line of Hearts & Arrows perfectly cut diamonds with one exception – they’re much cheaper. We’ve been eagerly recommending these diamonds since early 2012 and everyone that has followed our advice has been extremely pleased.
Otherwise, if you’re considering buying locally, despite the savings you might gain by buying a Strong Blue Fluorescent diamond, it will certainly still be cheaper for you to buy your diamond online and purchase either a Medium or lower fluorescence. Unfortunately, however, even James Allen with their advanced photography, cannot show you how the diamond will look face-up in direct sunlight.
If you have any questions, please post them in the comments below. I will usually respond within 24 hours.