Of all the 4Cs, Cut has the greatest effect on a diamond’s beauty. In determining the quality of the cut, the diamond grader evaluates the cutter’s skill in the fashioning of the diamond. The more precise the cut, the more captivating the diamond is to the eye. Grades cut on a scale from 0 to 10, with 0 being “Ideal” and 10 being “Poor”.
Color gem-quality diamonds occur in many hues. They range from colorless, to light yellow or light brown. Colorless diamonds are the rarest.
Other natural colors (blue, red or pink for example) are known as “fancy”, and their color grading is different than from white colorless diamonds. The Color of a diamond actually refers to the lack of color in a diamond, with perfectly colorless diamonds considered the highest quality with the highest value, and brown or yellow diamonds being the lowest quality. Color grades from D-Z.
Diamonds can have internal characteristics known as inclusions or external characteristics known as blemishes. Diamonds without inclusions or blemishes are rare; however, most characteristics can only be seen with magnification.
The modern clarity scale has a universal standard, using verbal descriptors:
Flawless, Internally Flawless, VVS1, VVS2, VS1, VS2, SI1, SI2, I1, I2, and I3.
The carat is the diamond’s physical weight measured in metric carats. One carat equals 1/5 gram and is subdivided into 100 points. Carat weight is the most objective grade of the 4Cs.