Color Grading
The Gemological Institute of America's (GIA) color reference chart
For fancy-colored diamonds, color far surpasses the other “Cs” (clarity, cut, and carat weight) when establishing value. Therefore, it is critical to understand color appearances and how they affect color grades and descriptions. While everyone thinks they understand color, for most it is an intuitive response rather than a true knowledge of the ordering of color appearances.
Color is described using three attributes:
· Hue (the aspect that permits an object to be classified as red, green, blue, violet, or anything in between)
· Tone (the relative lightness or darkness)
· Saturation (the relative strength or weakness)
