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Diamond Fluorescence: Good or Bad? What You Need to Know
Diamond fluorescence is one of the most misunderstood characteristics in the diamond world. Some shoppers avoid it, others seek it out—but most don't really understand what it is. Let's clear that up.
What Is Diamond Fluorescence?
Fluorescence is the visible light some diamonds emit when exposed to ultraviolet (UV) rays. About 25-35% of diamonds exhibit some degree of fluorescence, and in almost all cases, the color is blue.
Fluorescence Grades
- None: No visible fluorescence under UV light
- Faint: Barely detectable
- Medium: Noticeable under UV light
- Strong: Easily visible under UV light
- Very Strong: Intense glow under UV light
Does Fluorescence Affect Appearance?
In most cases, fluorescence has no visible effect on how a diamond looks in normal lighting conditions. However:
- In lower color grades (I-M): Blue fluorescence can actually make a yellowish diamond appear whiter in daylight—a positive effect!
- In higher color grades (D-F): Strong fluorescence can occasionally make a diamond appear slightly hazy or "milky"—though this is rare (affects less than 2% of fluorescent diamonds)
The Price Advantage
Here's the insider tip: diamonds with fluorescence are priced 5-15% lower than equivalent non-fluorescent stones. For medium to strong fluorescence in the G-J color range, you're getting:
- A diamond that looks identical (or even better) in everyday light
- At a meaningful discount
- With a cool party trick under blacklights!
Our Recommendation
Don't automatically rule out fluorescent diamonds. For G-J color grades, medium blue fluorescence is often a benefit, not a drawback. Always evaluate the specific diamond—if it looks beautiful to your eye, that's what matters.
At Katarina, we evaluate every diamond individually. If a fluorescent diamond passes our quality standards, it's in our collection—because beauty is what you see, not what a lab report says.
