A Brief History of GIA Cut Grading Systems

In the 1950s, the GIA established a system for grading diamonds based on the Four Cs — color, clarity, cut, and carat, which proved to be a great asset to the diamond industry. This system greatly improved the standards for evaluating color and clarity. However, the standards for evaluating the cut left something to be desired. To be fair, establishing a simple and usable system that would cover all the variables involved in the cut was very challenging.

The 2005 GIA diamond cut grading system finally accomplished this. Rather than placing cuts into four classes by calculating how close a cut stone came to an ideal set of proportions, the new system evaluates how the individual elements of the cut combine to affect the appearance of the diamond. There are now five grades, which indicate how well the cut affects a stone’s performance. In addition, the GIA allowed some flexibility in the system for personal preferences. Table size is a prime example of this.

What are the 2005 GIA Diamond Cut Grades?

The GIA assigns the cut of a diamond one of the following grades:

  1. Excellent (the best grade)
  2. Very Good
  3. Good