Fluorescence is the tendency of a diamond to emit a (soft) glow when exposed to ultraviolet light (UV light). The fluorescence effect is present in over 30% of diamonds and is an important consideration when buying a loose diamond.
When UV light strikes a diamond with fluorescent properties, the stone emits a glow. Most often blue, it can also be shades of green, yellow, white or red. Fluorescence can occur in different intensities. Gemological laboratories like the GIA rate diamond fluorescence on a scale from "None" to "Very Strong". (Want to speak with a diamond expert? Call 866-737-0754 for expert advice on fluorescence.)
- None, Nil, Negligible
- No fluorescence, no influence on color.
- Faint, Slight
- Weak fluorescence, not a significant influence on color (barely perceptible).
- Average fluorescence, small influence.
- Strong, Extremely Strong
- Strong fluorescence, substantial color influence.