C2: Color
The color of a Diamond has a significant impact on the stated value. The diamond color scale ranges from D to Z, from colorless to light yellow, respectively. The farther from colorless the grade of a diamond, the less rare and therefore less valuable it is. When buying a diamond, take into consideration that it is often very difficult to detect the difference between a colorless diamond (D-F) and a near colorless diamond (G-H), especially when it is mounted in jewelry. Diamonds with a J-Z color grade usually have yellow shading that can be detected by the naked eye. A well cut stone with good proportions will still release the brilliance and fire of a lower colored diamond, dispersing light in such brilliance to be a beautiful stone.
Diamonds also come in a range of natural fancy tones, including blue, pink, green, and red. Natural Fancy Tone Diamonds have so much color that they are not graded on the normal scale D-Z. Fancy Tone diamonds are particularly rare, and are equally valuable. Color does not have an exclusive impact on a diamond’s value. The value of a stone is affected by a combination of qualities including shape, clarity, cut, and carat weight.
D COLOR GRADE DIAMOND
Absolutely colorless diamond. The highest color grade, which is extremely rare.
E COLOR GRADE DIAMOND
Colorless. Minimal traces of color that can only detected by an expert gemologist. Also, a very rare diamond.
F COLOR GRADE DIAMOND
Colorless. Slight color, which can only be detected by an expert gemologist, but still considered a “colorless” grade.
G-I COLOR GRADE DIAMOND
Near-colorless. Color noticeable when compared to diamonds of better grades, but these grades offer excellent value.
J-K COLOR GRADE DIAMOND
Near-colorless. Color slightly detectable.
L-N COLOR GRADE DIAMOND
Noticeable to the untrained eye.
O-S COLOR GRADE DIAMOND
Not carried or recommended.
T-Z COLOR GRADE DIAMOND
Not carried or recommended.
Fluorescence
The bluish glow that comes from a stone exposed to ultraviolet light is the Fluorescence. The effect of fluorescence depends on the combination of the color of the stone in question and the strength of the fluorescence. Faint fluorescence has very little effect on a stone of any color. Medium blue fluorescence and strong blue fluorescence can have a positive effect on stones of low color (J or worse). The fluorescence actually has the effect of making the stone look closer to near colorless. On stones of high color (D-G), strong or medium blue fluorescence can make the stone look milky instead of colorless or near colorless.