Do you know how diamond color is evaluated? GIA kicks off its 4Cs Q&A series with color grading.
A: Before GIA established the D-to-Z Color Grading Scale, a variety of other systems were used loosely, from A, B, and C (used without clear definition), to Arabic (0, 1, 2, 3) and Roman (I, II, III) numbers, to descriptive terms like “gem blue” or “blue white,” which are notorious for misinterpretation. So, the creators of the GIA Color Scale wanted to start fresh, without any association with earlier systems. Thus, the GIA scale starts at the letter D. Very few people still cling to other grading systems, and no other system has the clarity and universal acceptance of the GIA scale.
Q: How is diamond color evaluated?
A: Light source and background can have a significant impact on a diamond’s appearance, so GIA grades color in a standardized viewing environment against color masters. A minimum of two GIA color graders enter independent evaluations of each diamond. Depending on the agreement of these grades and the weight and quality of the diamond, additional GIA graders may enter their own color opinions. The grade is not determined until there is sufficient consensus.
Color diamond images are for reference only and may not reflect true diamond color quality grades. Images are not for color diamond grading.
Updated: GIA report scales have been updated with the newest scales as of May 2014