Fluorescence In Diamonds

What Is Diamond Fluorescence?

Diamond fluorescence is a natural effect where a diamond emits a visible glow when exposed to ultraviolet (UV) light. The glow is most commonly blue, although some rare diamonds show yellow, orange, green, or even white fluorescence.

Fluorescence intensity is graded on a scale in diamond grading reports from GIA, AGS, HRD, IGI, and EGL:

• None – No visible fluorescence.

• Faint – Barely detectable glow.

• Medium – Noticeable under UV light, but usually not visible otherwise.

• Strong – Strong glow under UV light, may slightly affect appearance.

• Very Strong (Extreme) – Intense glow, can cause haziness or oiliness.

How Does Fluorescence Affect a Diamond’s Appearance?

The impact of fluorescence on a diamond depends on its colour grade and fluorescence intensity:

• Faint to Medium Fluorescence

  • Often improves the appearance of diamonds in the near-colourless range (G–J) by neutralising yellow tones with its blue glow.

  • Does not negatively affect brilliance or sparkle.

  • Usually results in a 10–20% price discount, making them great value.

• Strong to Very Strong Fluorescence
  

  • Can make diamonds look hazy, oily, or cloudy, especially in higher colour grades like D, E, and F.

  • While such stones are discounted by up to 25%, they should be evaluated carefully.

  • Some strongly fluorescent diamonds still look stunning – evaluation should be case by case.

💡 Fun Fact: About 30% of diamonds display some level of fluorescence.

Market Perception of Fluorescence

Historically, strongly fluorescent diamonds – called “Blue-White diamonds” – were highly desirable and fetched premium prices. Today, however, the market often views fluorescence as a flaw, which paradoxically lowers prices even though it is a rare natural trait.

When Is Fluorescence Beneficial?

• Best for diamonds in the G–J colour range, where faint to medium fluorescence can make them look whiter.

• Buyers seeking value for money can choose diamonds with medium fluorescence and enjoy both beauty and savings.

• Ideal for markets with strong sunlight or UV presence (Australia, South Africa, USA), where fluorescence can enhance whiteness outdoors.

When to Be Cautious With Fluorescence

• For colourless diamonds (D–F), strong fluorescence may cause a milky or oily look.

• For investment-grade diamonds (D-IF, D-Flawless), fluorescence generally reduces resale value.

• Always request to view the diamond under UV light before purchasing.

FAQs About Diamond Fluorescence

Q1: What is diamond fluorescence?
A: It is the visible glow diamonds emit under UV light, usually blue.

Q2: Does fluorescence affect diamond colour?
A: Yes. Faint to medium fluorescence can make lower colour grades (G–J) appear whiter. Strong fluorescence may negatively affect appearance.

Q3: Is fluorescence good or bad?
A: It depends. For near-colourless diamonds, faint to medium fluorescence is a benefit. For colourless diamonds, strong fluorescence may be a drawback.

Q4: Does fluorescence reduce diamond price?
A: Yes. Diamonds with fluorescence are often 10–25% cheaper than non-fluorescent equivalents.

Q5: Can fluorescence be seen without UV light?
A: No. Fluorescence is only visible under strong UV lighting, such as sunlight or a UV lamp.

Q6: How common is fluorescence in diamonds?
A: Roughly 25–30% of diamonds exhibit some degree of fluorescence.

Q7: Should I avoid diamonds with fluorescence?
A: Not necessarily. Faint to medium fluorescence is often a bonus. Just avoid strong/very strong fluorescence unless reviewed by a professional.

Professional Advice for Buyers

If you are shopping for a diamond:

• For value: Choose a G–J colour diamond with faint to medium fluorescence – it looks whiter and saves money.

• For investment-grade stones (D–F, IF, VVS): Avoid fluorescence, as it may reduce value.

• Always buy from a trusted jeweller who can show fluorescence under UV light.

Conclusion – Should You Buy a Diamond With Fluorescence?

Fluorescence in diamonds is neither entirely good nor bad – it depends on the stone’s characteristics and your priorities. For many buyers, faint to medium fluorescence is an advantage, offering beauty and savings. For perfectionists and investors, non-fluorescent diamonds remain the safest choice.

At ComparetheDiamond.com, we provide expert guidance, certified stones, and transparent reports so you can confidently choose the diamond that best fits your style, budget, and values.