Diamond fluorescence is a form of illumination that is created when a diamond is exposed to Ultraviolet (UV) light.
About a third of all diamonds will glow under ultraviolet light, usually a blue colour which may be noticeable under a black light or strong sunlight.
According to the GIA, who reviewed a random sample of 26,010 natural diamonds, 65% of the sample had no fluorescence. Of the 35% that did have fluorescence, 97% had blue fluorescence of which 38% had faint blue fluorescence and 62% had fluorescence that ranged from medium to very strong blue.
Other colours that diamonds can fluoresce are green, yellow, white and red but are very rare and are sometimes a combination of the colours such as blue-green or orange.
