The 4Cs of diamonds refer to Cut, Color, Clarity, and Carat Weight. These factors are universally used to assess the quality and value of a diamond. The cut determines how well a diamond reflects light, affecting its sparkle and brilliance. Color refers to the lack of color in a diamond, with the most valuable diamonds being colorless. Clarity measures the presence of internal and external flaws, known as inclusions and blemishes. A higher carat weight typically indicates a larger and more valuable diamond.