The 4 C's When selecting a diamond, it is important to have an understanding of the 4 C's. But what are the 4 C's and what in the world do they actually mean? Here is a brief explanation of cut, carat weight, color, clarity, and what they mean when you are picking a diamond. Cut Carat Color Clarity   Due to minute traces of minerals trapped in a diamond during the crystallization process, every diamond is unique. These natural characteristics, called inclusions or blemishes give the diamond its own individuality. Clarity refers to the number, color, size, and position of inclusions. To determine a diamond's clarity grade, it is viewed under 10-power magnification by a trained diamond grader. A flawless diamond has no external blemishes or inclusions. The closer to flawless a diamond is, everything else being equal, the greater the value of that stone. Under the GIA rating scale, most diamonds sold in jewelry stores are between SI1, and I1 in clarity.