Diamond Cut Grade

• The Gemological Society of America ranks diamond cuts as excellent, very good, good, fair and poor. These are based on the diamond's proportions, symmetry and polish.
  
  

Polish

• This refers to a diamond's surface quality. Nicks and abrasions decrease a diamond's value.
  
  

Symmetry

• A diamond's value increases when its shape and the alignment of its facets are symmetrical.
  
  

Depth

• If a cut is too shallow, it will lose brilliance when light leaks from the bottom. A diamond cut too deep can appear dark because it loses light from its sides.
  
  

Shape

• Diamonds come in a variety of shapes, including round, oval, pear and heart. All of these shapes match their names. An emerald cut diamond is rectangular with cut corners, while a princess cut is a square shape. Trilliant cuts take on a triangular, wedge shape, and radiant cuts have a square or rectangular shape with more facets and increased brilliance. Cushion cuts are large, rectangular shapes with rounded corners similar to those common in the late 19th century.