Understanding Diamond Fluorescence
About 25-35% of diamonds exhibit fluorescence—a glow under UV light. Is it a flaw to avoid or a feature that can save you money? Here's everything you need to know.
What is Diamond Fluorescence?
Fluorescence is a diamond's tendency to emit a soft glow when exposed to ultraviolet (UV) light. This is caused by trace elements (usually nitrogen) in the diamond's crystal structure.
The most common fluorescence color is blue, though yellow, green, and white fluorescence also occur. Under normal lighting conditions, fluorescence is rarely visible.
Important Fact
A GIA study found that the average person cannot distinguish fluorescent from non-fluorescent diamonds in normal viewing conditions. Even trained gemologists often can't tell without UV light.
Fluorescence Levels Explained
None
No visible fluorescence under UV light
Premium price (0-5% more)
No change in any lighting
Faint
Barely detectable glow under UV
Standard price
Virtually undetectable to naked eye
Medium
Noticeable glow under UV light
5-10% discount
Rarely visible in daylight
Strong
Obvious glow under UV light
10-15% discount
May appear hazy in some diamonds
Very Strong
Intense glow under UV light
15-30% discount
Higher chance of haziness
Should You Choose a Fluorescent Diamond?
When Fluorescence is Beneficial
- Lower color grades (I-M): Blue fluorescence can make yellowish diamonds appear whiter and more colorless.
- Budget-conscious buyers: You get a visually identical diamond at 10-15% less.
- Unique appeal: Some people love watching their diamond glow under blacklights.
When to Avoid Fluorescence
- High color grades (D-F): Strong fluorescence can make colorless diamonds look slightly hazy or oily.
- Investment purchases: Non-fluorescent diamonds have better resale value.
- Maximum sparkle priority: Very strong fluorescence may slightly reduce brilliance.
Thailand Shopping Tip
Bangkok's strong sunlight contains significant UV rays. If you're buying a diamond with strong fluorescence, view it outdoors in Thai sunlight to see how it performs in your everyday environment.
The Smart Buyer's Strategy
For D-F Color Diamonds
Stick to None or Faint fluorescence to avoid any risk of haziness affecting the premium color.
For G-H Color Diamonds
Medium blue fluorescence is often a sweet spot—potential discount with minimal visual impact.
For I-K Color Diamonds
Strong blue fluorescence can actually improve the appearance by counteracting yellow tints. Great value opportunity.
Find Your Perfect Diamond
All diamonds at GlitzJewelry.com include fluorescence information so you can make an informed choice.
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