Answer: Carat Weight
Explanation: The "four Cs" of gemstone grading are a standard system used to assess and evaluate the quality and value of a gemstone. They are:
Cut: Refers to the gemstone's shape, proportions, and facets, which can affect its brilliance and sparkle.
Color: Describes the hue, tone, and saturation of the gemstone's color. The more intense and vivid the color, the more valuable the gemstone tends to be.
Clarity: Refers to the presence of any inclusions or blemishes within the gemstone. Gemstones with fewer flaws are considered more valuable.
Carat Weight: Represents the gemstone's weight, where one carat is equal to 200 milligrams. Larger gemstones of the same quality are generally more valuable.
So, the answer to your question is that "Carat Weight" is not one of the four Cs of gemstone grading, as it is indeed one of the four Cs.