Diamond fluorescence refers to a diamond’s tendency to emit a soft colored glow when subjected to ultraviolet light (such as a “black light”). Usually fluorescence is unnoticed by the human eye in ordinary light.
The fluorescence of a diamond are graded by its intensity and is usually described as either None, Faint, Medium, Strong, or Very Strong. For diamonds with very high colors (D, E, and F), Strong fluorescence is considered less desirable. On the other hand, for diamond with slightly lower colors (J and below), Strong fluorescence is preferred.
Listed below is a list of abbreviations used to describe the strength of fluorescence:
- N, NO, NON – No Fluorescence
- F, FB, FT, FA – Faint or Faint Blue Fluorescence
- SL, SLB, SLT – Slight Fluorescence
- M, MO, ME, MD – Medium or Moderate Fluorescence
- S, ST, STB, STG – Strong Fluorescence
- VSB – Very Strong Blue
- E, EX, EXB, EF – Extreme Fluorescence