Diamond Fluorescence Guide
Discover the effects of fluorescence on diamonds.
Fluorescence describes how a diamond reacts when exposed to ultraviolet (UV) light, such as sunlight or a blacklight. Some diamonds emit a soft glow — most commonly blue — while others show no reaction at all. Fluorescence doesn't affect a diamond's durability, and in most cases has little to no visible effect on its appearance in normal lighting.
Fluorescence Intensity Scale
| Intensity | Description |
|---|---|
| None | No visible reaction under UV light. The diamond's face-up appearance is unaffected by fluorescence entirely. |
| Faint | A very slight glow that's essentially undetectable without specialized equipment and has no impact on appearance. |
| Medium | A noticeable glow under UV light, though it typically has no visible effect on the diamond under normal lighting conditions. |
| Strong | A pronounced glow under UV light. In rare cases, strong fluorescence can add a very slight haziness, particularly in higher color grades. |
| Very Strong | The most intense reaction to UV light. Occasionally used deliberately, as strong blue fluorescence can make a lower color-grade diamond appear whiter in daylight. |