Diamond Fluorescence

Is fluorescence in a diamond good or bad?

When purchasing a diamond, its important to take fluorescence into consideration. Depending on the diamond, fluorescence can either improve the diamond’s color or make it appear hazy. In this guide, we share how to evaluate fluorescence in diamonds. 

So if you’re wondering what diamond fluorescence is, think about how ultra-violet light makes your whites look whiter and your blacklight posters glow. In the same way, some diamonds fluoresce when they’re under UV light. 

Fluorescence in diamonds is the glow you might see when the diamond is under ultra-violet (UV) light (i.e. sunlight or black light). Approximately 30% of diamonds glow at least somewhat.

When exposed to ultra-violet light, these diamonds glow in different colors. 99% of the time, the glow is blue, but on rare occasions, diamonds glow white, yellow, green, or even red in color.

The GIA grades this glow in diamonds as None, Faint, Medium, Strong and Very Strong

But is Diamond Fluorescence Good or Bad?

Fluorescence can be both good or bad: it can improve a diamond’s color or make the diamond look hazy. When diamonds have Slight or Faint Blue Fluorescence, for example, they don’t appear cloudy.

In fact, the slight fluorescence can make the diamond appear more white. But when fluorescence makes the diamond hazy, the stone is less transparent. Light won’t reflect as well and the diamond won’t be as clear or beautiful.

  • Strong or Very Strong Blue Fluorescence: These diamonds usually appear hazy or cloudy.
  • Medium Blue Fluorescence with a high Color grade (G or better): These diamonds also usually appear milky or hazy.
  • D, E and F Color diamonds with any Fluorescence:
    Diamonds in the colorless range (D-F) don’t benefit from fluorescence. They’re actually considered less valuable, so their price and desirability are also lower.
Blue Fluorescence in Diamonds

Most diamonds exhibiting Strong Blue Fluorescence appear slightly to severely hazy in regular lighting conditions.

Tips on Diamond Fluorescence

  • Fluorescence can often improve the color of the diamond
  • Strong blue fluorescence does not necessarily mean there will be a negative effect on the diamond’s overall color and appearance
  • Faint fluorescence of a diamond can actually save you money without having to miss out on brilliance
  • Buy fluorescent diamonds from a reputable jeweller such as Kanjimull to ensure they’re high-quality
  • When shopping, it is okay to ask to see the diamonds under UV and normal lighting, as well as inquire about how it may look when exposed to daylight
  • Strong/Very Strong Blue Fluorescent diamonds usually appear hazy
  • Medium Blue Fluorescent diamonds rarely appear hazy
  • Slight/Faint Blue Fluorescent diamonds never appear hazy

Fluorescence can improve color

Some studies done on fluorescence claim that it usually improves the appearance of color in the diamond.

If you are buying a diamond with a color H or lower, seek out a diamond with Medium Blue Fluorescence.

A medium blue fluorescent diamond color can even help counteract any yellowish tint the diamonds may have and can make them appear much whiter. In effect, this will make the diamond color and appearance an entire color grade higher.

Fluorescence can make the diamond shine and sparkle more than a diamond that lacks fluorescent properties.

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