April 12, 2023 3 min read

The process of grading diamond color has come a very long way since its inception in sixth-century India. Back then, the system was deeply rooted in the country's ancient class structure, with different castes being allowed to own and wear diamonds of specific colors as a symbol of their rank. Today, the world of diamond color grading has evolved significantly, with well-established methods that focus on more than just vague comparisons. Together we will explore the history of diamond color grading and the modern-day GIA system that has become the worldwide standard.


The Ancient Indian System


In ancient India, the color of diamonds was used as a symbol of rank, and members of different castes were allowed to own and wear diamonds of specific colors. Brahmins, who were priests and rulers, were allowed to own white or colorless diamonds, while landowners and warriors were assigned brown diamonds. The merchant class could own only yellow diamonds, and the lower classes were allowed gray or black diamonds. Kings, however, could possess diamonds of any color.


The Rarity-Value Relationship


Diamond value is directly proportional to its rarity. Colorless diamonds are the rarest and most valuable in the normal color range. In contrast, fancy-colored diamonds, those outside the normal color range, hold the highest value when they exhibit saturated pinks, blues, and greens. Even slight variations in color can significantly impact a diamond's value.


The GIA Color Grading System


The Gemological Institute of America (GIA) began a color-grading system for diamonds in the 1950s to eliminate the vagueness of previously used trade terms. The GIA Color Scale, which is now widely recognized and respected worldwide, ranges from D (colorless) to Z (light yellow). This system provides a basis for color comparison using a set of masterstones assembled by GIA, representing the various levels of color depth.


D-to-Z Range

Masterstones represent various color depths, from colorless to progressively deeper yellow hues. Whole grade masterstones, such as H or I, indicate the least color in that grade. For instance, a diamond with less color than an H would receive a grade of G or higher. Split-grade masterstones, like H-I, represent the color approximately halfway between the two grades, meaning an H-I split-grade masterstone signifies the middle of the H-grade.


Diamonds within the standard color range are assessed based on their absence of color. Since subtle color differences are more noticeable through the pavilion, these diamonds are graded face-down, or table-down. This method minimalizes confusion caused by brilliance and fire, providing the best view of the diamond's color. Fancy-colored diamonds, on the other hand, are graded face-up or table-up.


The GIA Color Scale ranges from D (colorless) to Z (light yellow). A diamond's color grade depends on the tone and saturation of its color, or lack of. Each letter signifies a narrow color range rather than a specific point, with masterstones marking the highest point or least color within that range. Diamonds with slightly less color than a specific masterstone receive the next higher color grade.


The GIA Color Scale is divided into colorless, near-colorless, faint yellow, very light yellow, and light yellow ranges. D-E-F grades are considered colorless, G-H-I-J grades are near-colorless, K-L-M grades are faint yellow, N-R grades are very light yellow, and S-Z grades are light yellow. The value of a diamond can be dramatically impacted by its color grade, with the most considerable price jump occurring between D and E grades. The importance of precise color grading is highlighted by the notable value differences further down the color scale.


Brown diamonds within the D-to-Z range are graded with modifications, while gray diamonds with color equal to or greater than the K masterstone use the fancy-color system. The GIA D-to-Z color scale emphasizes the importance of accurate color grading due to the considerable impact it has on a diamond's price.

Trade Terms and Their Limitations


Before the GIA system, diamond color was described using location-based trade terms. These terms were often vague and subject to misinterpretation, leading to inaccuracies in diamond color grading. The GIA color-grading system, however, prevents many of these issues by using strict guidelines and accommodating the subtle nuances of diamond color, providing a consistent and accurate way to communicate about diamond color worldwide.



Diamond color grading has evolved dramatically since its origins in ancient India. The modern GIA system ensures consistency and accuracy, providing a reliable method for assessing diamond color. As a result, today's diamond buyers can be confident in the color grades assigned to the precious stones they purchase, knowing that the grading process is rooted in a well-established and world-respected system.