Diamond Color Grading Scale
Diamonds are graded on a color scale implemented by the Gemological Institute of America (GIA), which ranges from D, which is colorless, to Z, which includes diamonds that have a light yellow or light brown tint to them. This color scale is used to evaluate a diamond's internal tint and plays a significant factor in determining its price. To date, white-colored diamonds remain the most popular, even though diamonds are found in a kaleidoscope of colors. A truly colorless is the most desirable and therefore generally the most expensive.
Color is graded under controlled lighting conditions, which is most like natural light since high intensity artificial lighting can make the diamond appear to be of a better color grade than it actually is. Color differences can be so subtle that diamonds being graded for color are also compared to a master set for accuracy. Diamonds should additionally be examined for fluorescence, as blue photoluminescence will also make the diamond appear to be of a better color grade. White-colored diamonds vary in color from colorless to slight tones of yellow or brown. Colorless and near colorless diamonds are the most brilliant, rare and valuable. However, while truly colorless diamonds, graded D, are treasured for their rarity, diamond color is ultimately a very personal taste.
The GIA (Gemological Institute of America) color grades
When a diamond is graded as Colorless, the tint is nearly undetectable to an unaided, trained eye, even when compared to white standard.
Near colorless (G-H)
The diamond with a Near Colorless grade of G-H shows that any tint is almost undetectable to the trained eye, but apparent when compared to white standard.
Near colorless (I-J)
When there’s only a trace of tint just detectable to the trained eye, but noticeably apparent when compared to white standard, this will earn the grading of Near Colorless I-J.
Faint yellow to faint brown (K-M)
If a tint is apparent to the trained eye and readily apparent when compared to white standard, the diamond will be graded as Faint Yellow to Faint Brown, or K-M.
Very light yellow to very light brown (N-R)
A tint that is easily apparent to the unaided, trained eye means that a diamond will be given a grade of Very Light Yellow to Very Light Brown, or N-R.
Light yellow to light brown (S-Z)
A diamond with a tint that is obvious to the unaided, trained eye is graded as Light Yellow to Light Brown, or S-Z.