Fluorescence – Good or Bad?

Fluorescence is a phenomenon that naturally occurs in diamonds when exposed to ultraviolet light. This can cause them to emit bluish light in some circumstances. The GIA (Gemological Institute of America) identifies the intensity of the fluorescence on their grading report by noting; None, Faint, Medium, Strong and Very Strong.

For most diamond buyers the general opinion is that the presence of fluorescence in an off-color stone (I color or below) can enhance the diamond’s color. It is seen as something beneficial in this circumstance. In higher white stones (H Color or Better) it can be seen a deterrent, especially with Strong or Very Strong Fluorescence where it can create a clouding effect. The GIA (Gemological Institute of America) recommends that the stones be inspected individually.