As most gemologists say cut is a very important factor of the Four Cs of diamond quality. A good cut diamond has "full life", meaning "brilliance". And lets face it, brilliance is what makes the diamond stand out, especially in the eyes of the consumer. The particular cut of a diamond is what determines its ability to handle light, which leads to brilliance.

Take a moment to look at the illustrations shown and you will see when a diamond is well cut (either excellent or an Ideal cut), light enters through the table and goes to the pavilion of the diamond where it reflects from one side to the other side of the diamond. However In a poorly cut diamond (either Fair or poor cut), the light that enters through the table of the diamond then reaches the pavilion facets and then the light disappears from the sides or bottom of the diamond rather than reflecting the brilliance back to the persons eye.

diamond anatomy photo
Diameter: This refers to the width of a polished gemstone measured through the girdle.
Table: The largest facet of a diamond.
Crown: The upper section of a diamond from the girdle to the table.
Girdle: The girdle refers the outer edge of a diamond.
Pavilion: The portion of the diamond below the girdle.
Culet: The culet is the bottom point of a diamond. Recommended grade "none" or "small").
Depth: Exceptional cut! Perfectly proportioned with the highest grade of polish and symmetry which virtually reflects nearly all light that enters the diamond. Ideal cut diamonds are the most brilliant, and expensive diamonds.
Excellent Cut: This grade of diamond virtually reflects almost all light but a bit less than the ideal cut.
Very Good Cut: This grade of diamond reflects a great amount of light that enters it. Reflects nearly as much light as the excellent cut, but with a lower price tag.
Good Cut: This grade of diamond is proportioned to reflect most light that enters it. These are a great value.
Fair Cut: Not a great choice of cut, but still allows some light to be reflected. Great diamonds for customers looking for a low price, and a bit below average cut.
Poor Cut: Poorly cut therefore the most light entering it is lost out of its sides and bottom.