The AGS 0–10 grading scale is easy to understand: the highest possible grade is zero, and the lowest is 10.
So, a diamond with a color grade of 3 has less color than a diamond with a color grade of 5. Natural diamonds having less color are rarer; therefore, they may cost more.
When writing the grades of a diamond using the AGS Scale, diamond Cut grade is first, then diamond Color, Clarity, then Carat Weight—in that order.
If a diamond possessing the finest diamond Cut grade is also colorless, free of inclusions and blemishes, and weighs one carat, it would be written as: 0/0/0–1.000 carat.