Diamond Fluorescence

Fluorescence is the glow that a diamond emits when exposed to ultraviolet light. The glow is usually blue, but shades of red, green, yellow, pink, white and orange can also be emitted.

Fluorescence has different strengths and GIA uses the following scale when rating this feature:

  • None – No fluorescence at all and no influence on color.
  • Faint – Depending on the diamond’s graded color, this level of fluorescence can visually make a diamond appear one shade brighter or whiter in the sunlight.
  • Medium – May or may not have an affect on a diamond’s appearance.
  • Strong – A majority of the time the appearance of the diamond will be negatively effected at this strength. This characteristic can be used to help the owner identify their diamond when magnification is not possible.
  • Very Strong – Has a substantial influence on a diamond’s appearance. A majority of these diamonds have a milky or oily look to them.

A significant difference in price can occur depending on the degree of fluorescence a diamond has. Most of the time, white diamonds with Strong fluorescence are priced significantly lower than diamonds with a fluorescence strength of None to Faint.

NADB only brokers diamonds with a fluorescence grade between None and Medium.