Diamond Cut

The GIA Diamond Cut Grade

A diamonds cut basically refers to how well the diamond has been cut from the rough. The cut is considered the most important attribute of a diamond. The cut of a diamond determines a diamonds brilliance. So the better the cut of a diamond the more sparkle a diamond has.

The sketches below illustrate different light returns based on how well cut the diamond has been.

The cut grade is based on all the proportions and angles of a diamond and placed in an optical measuring device called a Sarin machine. Depending on the results of these proportions and angles it will be given the appropriate cut grade.

The Gemmological Institute of America or the GIA introduced the cut grade on 1st January 2006 for the Round Brilliant diamond. Currently there is no other cut grade for any other shape. The options for the cut grade from GIA are, poor, fair, good, very good and excellent.

ZS Diamonds offers only the top three cut grades. These are "Good", "Very Good" and "Excellent".

An Excellent cut is sometimes referred to as an Ideal Cut diamond. This means that the diamond is perfectly proportioned. Ideal cuts are normally only Round Brilliant diamonds, but sometimes its possible to other shapes. Ideal cut diamonds are normally around 5% - 10% more expensive than the average cut.

Diamond Cut - Symmetry & Polish

The symmetry grade is also important as it is based on how well aligned the diamond facets are. Which also determines the amount of light is returned to the eye, i.e. the sparkle The options for the symmetry and polish grade from GIA are, poor, fair, good, very good and excellent.

ZS Diamonds offers only the top three symmetry and polish grades. These are "Good", "Very Good" and "Excellent".

The polish grade is not as important as the symmetry or cut grade, it controls only very slightly the light return. The polish grade refers to how smooth the diamonds facets are. If the grade of polish was poor or fair, the diamond may appear slightly blurred or dull. We would recommend that the polish grade should be Very Good or Excellent.