The absence of color is by excellence the characteristic denoting a technically perfect diamond. Each diamond presents variations of hue, tone and saturation.

The assessment of these three adjectives allows a classification of the diamond in a descending chromatic scale from D (colorless) to Z (tinted), in turn grouped into 5 categories (colorless, near colorless, faint yellow, very light yellow and light yellow).

The coloring is very difficult to analyze, usually imperceptible from the second category up to the untrained eye, but it has a big impact in the economic evaluation of the diamond.