On Grading Colored Diamonds

Unlike prized colorless diamonds, fancy color diamonds only occasionally fall under the D to Z color grading system formulated by the GIA and currently used by diamond tradesmen worldwide. From the letter K and outwards, diamonds can start to be classified as a particular color. Faint, very light, and light are all at the edge of colorlessness and it depends on whether or not they will be marketed as a white diamond or as a fancy colored one.

Beyond that the grading system stops. Colored diamonds are usually prized for the intensity of their rare color and not for the same level of brilliance or fire as their colorless counterparts, making the GIA’s color grading system ill equipped to tackle these rare gemstones. Instead of the helpful two-point slider provided in the GIA’s color grading chart, fancy colored diamonds fall under three distinct ranges; hue, saturation, and tone.

The Color Scales

Hue or the color of the gem stone simply refers to which color is present. Once beyond Z classification, colored diamonds fall under the category known as “fancy light.” This additional classification is for those diamonds that show as a particular color but still display the ideal diamond brilliance, fire, and facets.

Tone is the word used to describe the purity of the diamond’s color. Because natural diamonds were created by the random circumstances of nature, not all fancy colored diamonds contain the same amount of trace elements that provide their coloration. In this case, the preferred appearance for a colored diamond’s tone is known as “fancy vivid.”

Saturation is a term used to indicate the intensity or the amount of color present in the diamond. Generally considered to be darker than the other two fancy classifications, saturation doesn’t indicate the presence of pigment so much as an absence of light. Under this classification the diamond’s coloration doesn’t have to be pure, but present, and is known in the diamond trade as a “fancy deep.”