Color Metrics

Color Metrics

The color of a fancy stone is described using Munsell notation, which defines three attributes: Hue (H), Value (V), and Chroma (C).

The notation format is: H V/C.
Examples: 7.5R 6/4, 8.2BG 5.3/3.4.

The Munsell system represents 40 Hues arranged on a circle. Each Hue corresponds either to one of the five primary colors or to a mixture of two adjacent ones.
The primary colors are: Red, Yellow, Green, Blue, and Purple.

The following fields are used to describe the color:

• HVC (string) – exact Munsell coordinates, which may include fractional values. This specifies the precise position of the color between tabular Munsell chips as defined in the Munsell Book of Color.
• nearestHVC (string) – the Munsell coordinates of the closest tabular chip to the precise HVC.
• hueAngleDeg (float) – the angular position of the Hue on the Munsell circle, in degrees. A value of 0 corresponds to the beginning of the 2.5R segment. The positive direction follows the sequence: Red → Yellow → Green → Blue → Purple.

The diagrams below illustrate the positions of exact Munsell coordinates and their nearest tabular chip.