Gemological Characteristics

Since around 1900, experts in the field of gemology have developed methods of characterizing diamonds and other gemstones based on the characteristics most important to their value as a gem. Four characteristics, known informally as the four Cs, are now commonly used as the basic descriptors of diamonds; Carat, Clarity, Color and Cut.

There are four major gemological associations which “certify” diamonds: that is, define the four Cs of a diamond. While carat weight and cut angles are mathematically defined, the clarity and color are judged by the trained human eye and are therefore open to slight variance in interpretation.

Gemological Institute of America (GIA)
  • First laboratory to issue modern diamond reports
  • Holds the highest reputation amongst gemologists for its consistent, conservative grading.
American Gemological Society (AGS)
  • Not as widely recognized or as old as the GIA, but garners an equally high reputation.
International Gemological Laboratory (IGL)
  • Generally respected laboratory but suffers from a negative industry reputation for its grading practices, which are perceived by critics as being either less conservative or less consistent than the GIA and AGS.
European Gemological Laboratory USA (EGLUSA)
  • Good reputation among the trade for consistent and fair grading.
  • Not as widely known as GIA or AGS.