1. The Colorless Diamond
The most frequently found color of diamonds is white, actually free from color. The colorless diamond is the most popular .
The diamonds reflect the light and break it into a rainbow of colors. This small reflection of color, or flash, has no effect on the technical evaluation of the color.
Rare diamonds without a trace of color are graded D. This grade can vary from D to Z depending on the intensity of color, starting from absolutely free of color to light yellow, brown or grey.
The color of a diamond is affected by chemical impurities and/or structural defects in the atomic structure of the carbon crystal.
GIA / Grade - CIBJO / Coulor
- D - exceptionally white +
- E - exceptionally white
- F - extra white +
- G - extra white
- H - white
- I - J - white with slight trace of color
- K - L - slight hue
- M à Z - hue
The grading of the diamond’s color can only be executed on a single, unmounted stone. To determine the exact hue present in uncolored diamonds, a certified comparison diamond is used, which is presented by the GIA. The stones are examined in special white lighting. The stones used for comparison are chosen with the help of numerous criteria.
2. Degree of Fluorescence
The majority of uncolored diamonds will glow when exposed by ultraviolet light: this phenomenon is called fluorescence which is not directly linked to the color of a diamond but shows the amount of absorption of UV light.
The degree of fluorescence is defined by it’s intensity:
- None or Nil
- Slight or Faint
- very Strong
Colored or « Fancy » Diamonds
While a faint yellow hue (ranging from I to Z) can lower the value of a diamond, naturally colored diamonds can reach very high prices. The diamond exists in all colors, of which red is the most rare.
Because the diamonds are colored (and not slightly tinted) they are not classified by letter but by the name of the color and it’s intensity.
These rare colored diamonds are referred to as fantasy (or fancy) and are graded with the help of a group of different color characteristics, for example the hue and the saturation.
Colored diamondsare the most expensive because they are extremely rare. The most sought after are the most intense and heavily colored stones.
In this table the different hues and saturation in the yellow color are shown. These tables exist for every color (blue, pink, red etc.). The basic color of the diamonds can be graded by these characteristics. For example, a diamond is graded as Fancy Yellow, or Fancy Vivid Yellow.