Visual Effects of Blue Fluorescence in Ideal Cut Diamonds

The visual effects of blue fluorescence upon ideal cut diamonds is without a doubt, the most challenging factor of diamond grading for people to grasp. This is because there is a wealth of misinformation regarding the effects of strong blue and very strong blue upon the appearance of a diamond, the internet is full of articles warning consumers that they need to be careful when considering diamonds with blue fluorescence because they might be over-blue, or appear cloudy, milky, or foggy as a result of the fluorescence.

However a study conducted by the Gemological Institute of America (GIA) in 1997, which was published in Gems & Gemology magazine (a trade publication) stated: “For the experienced observers, we found that, in general, the strength of fluorescence had no widely perceptible effect on the color appearance of diamonds viewed table-down (diamonds are graded for color in this position from a side profile). In the table-up position (face-up, as would be set in a ring), diamonds described as strongly or very strongly fluorescent were, on average, reported as having a better color appearance than less fluorescent stones. In this study, blue fluorescence was found to have even less effect on transparency.”

The article also stated that “One interesting aspect of this study was that to the non-trade observers, which would be considered most representative of the jewelry-buying public, fluorescence had no overall effect on color appearance or transparency.

And finally the GIA determined that blue fluorescence affects fewer than 2% of gem quality diamonds in a negative manner, and the vast majority of those were over-blue diamonds which exhibited very strong to distinct blue fluorescence.

So what’s the big deal about blue fluorescence in diamonds?

Prior to the 1970’s diamonds with blue fluorescence were heavily sought after, high color diamonds which exhibited strong blue to very strong blue fluorescence were commonly referred to as “blue white diamonds” or “premier blue diamonds” and they were all the rage because blue has a tendency to cancel out yellow… so when the blue fluorescent molecules in a diamond are excited by being exposed to ultra violet light, they have the effect of filtering out some of the yellow tones that can be present in diamonds, especially those which are warmer in color.

Blue white diamonds were in such high demand that some disreputable jewelers installed blue light bulbs in their showrooms to fool people into thinking that the non-fluorescent diamonds in their display cases actually had fluorescence because they gave off a blue tone as a result of the light source… it was such a widespread problem, that the Federal Trade Commission actually had to issue a rule prohibiting jewelers from using the term Blue White to refer to any diamond which was not high color with strong to very strong blue fluorescence.

Rule 28 of the Federal Trade Commission’s Trade Practice Rules for the Jewelry Industry reads: It is an unfair trade practice to use the term “blue-white,” or any other term, expression, or representation of similar import, as descriptive of any diamond which under normal, north daylight or its equivalent, shows any color or any trace of any color other than blue or bluish.”

The demand for diamonds with blue fluorescence was derailed back in the 1970’s when an investment fund in Asia decided to omit diamonds with blue fluorescence from the parcels of diamonds which they were offering to their clients for investment. This was followed up by an expose on diamonds with very strong blue fluorescence which was televised in Korea in the 1980’s which primarily focused on the 2% of gem quality diamonds which are negatively affected by fluorescence, and movement against blue fluorescent diamonds took off from there full speed.

Are Brian Gavin Blue Fluorescent Diamonds over-blue?

The short answer is no, all of the diamonds selected for the Brian Gavin Blue collection of diamonds with blue fluorescence, have been personally evaluated by Brian Gavin to ensure that the only effect the fluorescence is having upon the diamond is positive, or nothing at all… the reality is that in most cases, medium blue fluorescence is little more than an identifying characteristic.

And I think that diamonds with blue fluorescence, like this 0.733 carat, F-color, VS-2 clarity, Brian Gavin Blue round diamond with strong blue fluorescence look absolutely incredible when viewed under black light, as pictured to the left. I took this diamond for a walk this afternoon, and examined it closely in a variety of lighting scenarios, including direct sunlight, and it doesn’t exhibit the slightest hint of cloudiness. In fact, it looked perfectly normal and I don’t see a hint of blue in this diamond when I look at it in normal lighting… but it is one very bright looking F-color diamond, and that is one of the things I love about diamonds with blue fluorescence!