The Four Cs, or 4 Cs, of gem grading are color, clarity, cut, and carat (weight) These are the four properties that gemologists use to determine the gemstone’s value. The grading system was developed in the 1940s by the Gemological Institute of America (GIA) and was originally used for grading diamonds only. However, today it is also used to grade other precious gems as well. Of all the 4 Cs, the cut is said to have the greatest effect on a stone’s beauty.
