B2C Jewels Grading System
Fluorescence
Fluorescence of a diamond is defined as the light emitted by it when exposed to ultraviolet rays. In better colors, fluorescence reduces brilliance while in weaker colors it adds more brilliance.
According to B2C Jewels Grading System, FL0 indicates no fluorescence in a diamond, FL1 (faint), FL2 (medium), and FL3 (strong) indicates diamonds with increasing proportions of fluorescence and FL4 denotes very strong fluorescence.
The diamond images above are exposed to a strong ultraviolet light source. The light intensity is identical for all photographs. All diamonds are colorless.
Each of the five grades, i.e. from FL0 (no fluorescence) to FL4 (very strong fluorescence) directly impact the overall color and hence the price of the diamond. This is explained in the example below:
Shape Size Color Clarity
 
Cut, Polish,
Symmetry
Fluorescence
 
Pricing
Difference from
First pointer (%)
Round 2.019 G VVS1 EX
no fluorescence
faint
medium
strong
very strong
 
-3.0
-8.7
-19.6
-23.3
The table above indicates the price difference between grades while other parameters remain constant. The prices are subjected to individual grade and market trends.
Fluorescence Color
Fluorescence can be of different colors depending on the nature and type of bonds that other elements form with carbon atoms of a diamond crystal. Fluorescence colors like white, blue, yellow, orange and green have direct impact on the overall color and price of a diamond.