One of the phenomena a diamond can exhibit is fluorescence. Fluorescence in a diamond can be detected by using a black light. When viewed under a black light, fluorescence in diamonds will glow with varying intensities and colors. Although diamond fluorescence does not impact the 4C’s of diamond grading, it can affect the value and appearance of your diamond. Diamonds with higher grades of D through H can be significantly lower in value if they exhibit strong fluorescence since this will detract from the appearance of the stone. Diamonds with lower grades, J and below, are often more attractive if they have a strong blue fluorescence.
Diamonds are subject to many different types of treatment that affect their color and clarity. The accepted standard is that any process altering the loose diamonds natural characteristics should be disclosed to the consumer. It is virtually impossible for traditional diamond grading standards to be applied to stones with altered clarity.