The degree of Fluorescence of a diamond

Fluorescence is one of the 8 quality criteria of a diamond

Fluorescence comes from the reaction of the diamond atoms when exposed to the energy of different rays including ultraviolet.

Fluorescence is the property of diamond to change or diffuse a color by excitation to rays such as X-rays or ultraviolet rays. The excitation of a diamond by ultraviolet rays most often generates a blue or green orange, yellow or even pink color. When a diamond is exposed to ultraviolet rays, and when it remains dark, it means that it has no fluorescence.

Some diamonds have a very strong degree of fluorescence predominantly blue when they are exposed to the sun's rays which can strongly alter their color, appearing whiter than they actually are. Diamond fluorescence standards are used to determine the degree of fluorescence. 30 to 40% of jewelery diamonds are fluorescent. The rarest diamonds are those that are not fluorescent. Medium, strong or very strong fluorescence results in a dévaluation  of the  diamond colors D to H. For tinted diamonds ( from color I ) this devaluation  does not  apply.

The qualifiers for expressing the degree of fluorescence of the diamond that you will find on the certificates of authenticity are as follows:

• Nil
• Slight or fair
• Average
• Strong
• Very strong