Diamond Color Education: What You Should Know

Although we generally think of diamonds as being colorless, they are actually formed in a range of colors. It is usually most desirable to have the least amount of color as possible because cut diamonds behave like prisms, meaning the less color a diamond has naturally, the more it will sparkle. However, slight tones of yellow or brown are very common, which can decrease a stone’s brilliance.

When grading a diamond’s color, differences in hue are evaluated. These differences are very subtle and they are difficult for the untrained eye to detect unless the stones are placed side by side.

The diamond color gradient scale uses the letters of the alphabet from “D” (colorless) to “Z” (heavily tinted yellow.) Colors in “E” or “F” grades can only be seen by expert graders and “G” to “J” grades often appear colorless when mounted. Subtle color may be seen by the untrained eye beginning at the “J” grade and most consumers can notice color in “K,” “L” and “M” grades. Grades lower than “M” show definite color and it is rare for jewelry to be set with stones with an “O” grade or lower.

Diamond Color Grading
Most diamonds are slightly yellow, and are graded according to the following scale:
D: Absolutely colorless, these diamonds have the highest color grade and are extremely rare.
E: Colorless. Slight color can be seen by a skilled gemologist, but these high-quality diamonds are given a “colorless” grade.
G-H: Near-colorless. When compared to diamonds of better grades, these diamonds display color.
I-J: Near-colorless. These diamonds display slightly detectable color.
K-Z: Color becomes increasingly more noticeable.
Z+: Vividly colored yellow stones, or diamonds of any other color. They are also known as "Fancy" diamonds.

Fancy Diamonds
Graded “Z+” on the color scale, fancy colored diamonds are very valuable and quite rare. Common colors include pink, blue, green and red and they can even be found in black and white. Given their rarity, colored diamonds are generally priced much higher per carat than “normal” diamonds. It is important to note, however, that a diamond’s setting can impact its color. A colorless diamond set in yellow gold may reflect the yellow hues of the metal. But a slightly yellow stone may actually appear lighter set in yellow gold!

The novelty of fancy colored diamonds aside, a truly colorless diamond is almost always considered to be most valuable. As such, diamonds with a grade of “D” to “F” are very expensive. If you are a purist, select a diamond with a grade of “D” to “F” with a fluorescence grade of none, faint, inert or negligible. If you want an excellent value, select a stone with a grade of “G” to “I” and a fluorescence grade of medium or strong blue.

Above all, the diamond you purchase should have a good balance of cut, color and clarity. And remember, even when a stone has a visible tint, as with grades “K” or above, it can still be very lovely if good clarity and cut are present.

Diamond Fluorescence
When viewed under ultraviolet light, some diamonds will fluoresce. This quality is highly desirable to some and highly avoided by others. Fluorescence is graded as none, faint, inert, negligible, medium, strong or very strong and only a trained gemologist can detect the visible effects of faint, inert, negligible and medium grades. A fluorescence grade of strong or very strong can make a diamond with a near-colorless grade look even whiter. However, fluorescence can also create a hazy or oily appearance.