Diamond fluorescence denotes the manner in which the diamond reacts when exposed to ultra-violet light. Some diamonds when exposed to UV light tend to glow in different colours. Nine out of ten instances the glow in diamonds is blue in colour. Infrequently, however, some can glow green, yellow, white and even red colours.
You should bear in mind, however, that the existence of fluorescence in a diamond is noticeable only when exposed to UV lights.
Fluorescence in a diamond certificate is classified as:
- Strong: Fluorescent diamonds generally look cloudy
- Medium: Fluorescent diamonds hardly look cloudy
- Faint: Fluorescent diamonds never look cloudy
- None: Fluorescent is non-existent in diamonds
According to GIA (gemmological institute of America), the strong blue fluorescence is almost entirely unnoticeable to the average viewer. This is a point of contention amongst diamond consumers. It is believed that the existence of fluorescence in a diamond may enhance its colour, especially those diamonds with relatively low colour, I to K colour diamonds.
In respect to its direct effect on the diamond price, diamonds with high grade colours, D to F, may devalued by up to 10%.