According to the GIA laboratory fluorescence is the visible light some diamonds emit when they are exposed to invisible ultraviolet rays. On the GIA diamond grading report, fluorescence refers to the strength, or intensity of the diamond reaction to long wave UV, which is an essential component of daylight. Fluorescence is very common, according to GIA over the last decade 25% to 35% of all the diamonds they graded exhibit some degree of fluorescence and only 10% of those shows strengths of fluorescence that may impact appearance. In more than 95% of the diamonds that exhibit fluorescence the colour seen is blue. In rare occasions the reaction colour is yellow, white or another colour. In the studies that GIA has done the majority of the diamonds the strength of the fluorescence has no widely noticeable effect on the appearance. In many instances, observers prefers the appearance of diamonds that have medium to strong fluorescence. According to GIA fluorescence does not compromise the structural integrity of the diamond.