Fluorescence in Diamonds: What to Know

What’s something you can’t see with the naked eye (but sometimes you can), doesn’t impact the value of a diamond (but sometimes it does), and only shows up about 30% of the time (but you should know about it)?

Introducing Fluorescence

Fluorescence is a phenomenon occurring in diamonds that shows up under ultraviolet light. When a diamond is hit with UV light, fluorescence will cause it to glow. Diamonds without fluorescence will be dark, while ones with strong fluorescence will often give off a bluish glow.

Of course, the likelihood of wearing your diamonds in ultraviolet light is pretty slim, but fluorescence could affect the look of your diamond. Some feel that fluorescence gives a diamond a bit of a milky, oily, or hazy look. On the other hand, diamonds with little color can be enhanced by fluorescence. This interesting quirk of nature is another reason to always have your diamonds evaluated by an experienced pro.

How fluorescence can affect the value

Because of its unpredictable impact, fluorescence can sometimes improve the value of a diamond, and sometimes decrease its value. In diamonds with little or no color (grades I-M), the blue effect can make the diamond appear even whiter and clearer. This enhances the value of the diamond. Alternatively, in a high color diamond (D-F rating) the fluorescence adds a slight haze and will cause the diamond to be sold at a discount.

Should you be on the lookout for fluorescence?

Most studies say that 25-35% of diamonds have some amount of fluorescence. Within that small percentage is a range from faint, to medium, to strong, to very strong. Most diamonds you see will not have it, but since it can impact the appearance and value it’s good to ask about it when shopping. While you won’t be wearing it under UV light, it’s good to look at diamonds under different types of light and decide if you like it.

According to the GIA (Gemological Institute of America), “…the overwhelming majority of diamonds, the strength of fluorescence has no widely noticeable effect on appearance. …it was found that the average person could not make a distinction between a diamond with fluorescence and a diamond without.” 

Our jewelers are trained to look for all the things that make a diamond so magical, including whether it has fluorescence. You can be sure we’ll always help you find a diamond you’ll fall in love with at Schwarzschild Jewelers.