Fluorescence vs. color grading...

[Lockout888]

GIA or AGS grades a diamond with medium blue or strong blue fluorescence - when they grade the color, do they take into account that the fluorescence can make the diamond appear whiter? Do they take the color and knock it down a grade?

 

[vanilla87]

They do NOT take the flourescence into account when grading colour. In certain lighting conditions the Fluor can make the diamond APPEAR whiter but it doesnt actually change the body colour.

 

[denverappraiser]

They color grade in a standardized lighting environment. This is a hot toic among gemologists because the amount of UV coming from the bulbs will vary with the age of the bulb and UV disapates quickly in air so the distance from the bulb and the stone is an important variable. ne upon a time the rule was to filter out the UV in the grading environment but they've backed of on that in recent years and with the introduction of the 'diamond dock' as a grading space.