AGS Diamond Grading System
The AGS 0–10 Diamond Grading System
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. 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.
In the American Gem Society Diamond Grading Standards, this would be known as the famed Triple Zero® or Triple 000.