No. When two diamonds of the same color grade are observed in strong ultraviolet sunlight. The fluorescence reaction of diamonds is not all blue fluorescence. Strictly speaking, the fluorescence reaction of diamonds refers to the intensity of colored light such as blue light or yellow light emitted by diamonds under strong ultraviolet irradiation, but the international price of diamonds with medium or above fluorescence will have a gap of 3%-5%.

Not all diamonds are fluorescent and orange-yellow, and diamonds with no fluorescence or weak fluorescence have no effect on the price of diamonds. When testing diamonds, major jewelry laboratories all over the world usually mark fluorescence indicators, including blue and yellow. Fluorescence reaction is a natural indicator of diamonds, and there are many kinds of fluorescence reactions, such as medium blue and pink. Diamonds with blue fluorescence are likely to be whiter than diamonds without fluorescence. And the fluorescence of diamonds is strong and weak. This indicator can be regarded as a general standard. GIA classifies the level of fluorescence reaction from low to high into NONE and weak, and it is impossible to judge whether a diamond is true or false only by whether there is fluorescence reaction.