Answer: Diamond fluorescence is the glow some diamonds emit when exposed to ultraviolet light. In most cases, faint to medium fluorescence has minimal impact on how the diamond looks and can even make lower‑colour stones appear whiter. Strong fluorescence may occasionally cause a hazy appearance, so it’s important to check the diamond in person.
- What is fluorescence? A natural response where certain diamonds glow under UV light.
- Fluorescence grades: None, Faint, Medium, Strong, Very Strong – as graded on certificates.
- Impact on appearance: Usually none; only very strong fluorescence can make a diamond look cloudy.
- Impact on price: Diamonds with noticeable fluorescence often sell at a discount, offering value for budget‑savvy buyers.
| Fluorescence grade | Effect on appearance | Price impact | Best for |
|---|---|---|---|
| None | No glow under UV; colour and clarity unchanged | No discount | Buyers wanting the highest traditional quality |
| Faint | Barely visible blue glow under UV | Little to no price reduction | Good value for near‑colourless stones |
| Medium | Soft glow under UV light; usually no visible effect | Moderate discount | Budget‑savvy shoppers who prioritise appearance over rarity |
| Strong or Very Strong | Noticeable glow; may cause a slight hazy or milky look | Larger discount | Buyers who can inspect in person or like unique fluorescence |
FAQs
Does fluorescence make a diamond look blue?
Fluorescence is only visible under ultraviolet light and generally appears blue; however, in normal lighting conditions you won’t notice it.
Should I avoid diamonds with strong fluorescence?
Strong fluorescence can sometimes make a diamond appear oily or cloudy. It’s wise to view the diamond in different lighting before purchasing, but many strongly fluorescent stones still look beautiful and can offer savings.