Diamonds that belong to the type IIb group tend to have a blue hue. But when exposed to high-energy light, such as ultraviolet (UV) light, these diamonds can emit a captivating glow for a short period of time. This phosphorescence can range from blue to pink and deep red, depending on the diamond. Fluorescence in diamonds is the brightness that can be seen when the diamond is under UV light.
About 30% of diamonds will shine under this light, and the GIA rates diamond fluorescence as None, Weak, Medium, Strong and Very Strong. When diamond contains certain chemical impurities, it is likely to emit a glow when exposed to ultraviolet light. When comparing diamonds to each other, you will definitely see a difference between a diamond with a strong fluorescence and one with little or no. This extreme level of haze for a fluorescent diamond is not typical and is not as common as you might think when talking about diamonds that are H or below. If you buy a diamond in person, you can specifically order one with strong blue fluorescence. This characteristic of natural diamonds can also help solve one of the biggest problems in the diamond market: identifying fake gems with an authentic look.
The problem with some buyers is that they judge whether a diamond is fake or real based on how it shines in different light conditions. But after observing the afterglow of the world's largest deep blue diamond, experts discovered a unique method to select synthetic diamonds from natural gems and help identify stolen diamonds. To learn more about these brilliant phosphorescent gems, chemical engineers at the Gemological Institute of America studied the Aurora Heart Collection, which contains 239 colored diamonds and a series of type IIB blue stones, in addition to the Smithsonian's Esperanza diamond and its blue heart diamond. Because each and every diamond is different, scientists realized that they could use the color of the glow and how quickly the shine fades as a type of fingerprint to identify individual gems. Brightness is thought to be an interaction between ultraviolet light, boron found in blue diamonds, and nitrogen in stones. After being exposed to this light, each of the Type IIB natural diamonds shone for several seconds. In general terms, diamond fluorescence is blue, but from time to time, a diamond is seen to fluoresce another color, such as yellow.