WHAT IS DIAMOND CUT?
A quality cut grade allows a diamond to express its natural sparkle and scintillation.
Cut refers to the quality of a diamond’s proportions and symmetry. These angles allow the diamond to capture light and reflect it, producing sparkle. If a diamond’s pavilion is too deep, for example, the center will be noticeably dark.
If you want a truly brilliant diamond, consider those with cut grades of Very Good or Ideal.
A Diamond’s Cut Unleashes Its Light
Diamonds are renowned for their ability to transmit light and sparkle so intensely. We often think of a diamond’s cut as shape (round, heart/oval/marquise, pear), but a diamond’s cut grade is really about how well a diamond’s facets interact with light.
Precise artistry and workmanship are required to fashion a stone so its proportions, symmetry, and polish deliver the magnificent return of light only possible in a diamond.
A diamond’s cut is crucial to the stone’s final beauty and value. And of all the diamond 4Cs, it is the most complex and technically difficult to analyze.
To determine the cut grade of the standard round brilliant diamond – the shape that dominates the majority of diamond jewelry – GIA calculates the proportions of those facets that influence the diamond’s face-up appearance. These proportions allow GIA to evaluate how successfully a diamond interacts with light to create desirable visual effects such as:
Brightness: Internal and external white light reflected from a diamond
Fire: The scattering of white light into all the colors of the rainbow
Scintillation: The amount of sparkle a diamond produces, and the pattern of light and dark areas caused by reflections within the diamond
GIA’s diamond cut grade also takes into account the design and craftsmanship of the diamond, including its weight relative to its diameter, its girdle thickness (which affects its durability), the symmetry of its facet arrangement, and the quality of polish on those facets.
The GIA Diamond Cut Scale for standard round brilliant diamonds in the D-to-Z diamond color range contains 5 grades ranging from Excellent to Poor.
How does pavilion depth affect a diamond’s cut?
The distance from the bottom of the girdle to the culet is the pavilion depth. A pavilion depth that’s too shallow or too deep will allow light to escape from the side of the stone or leak out of the bottom. A well-cut diamond will direct more light through the crown.
Tremendous sparkle. Excellent polish and symmetry.
Lots of sparkle. Great polish and symmetry.
A good amount of sparkle. Sufficient polish and symmetry.
Will not sparkle very much. Unsatisfactory polish and symmetry.
The term “cut” has two references: One is the diamond’s shape, the other is the quality, determined by its proportions, symmetry and polish.
The top-selling diamond cut shape is the round brilliant. Other cut shapes including princess, marquise, pear, heart, oval, emerald, radiant, cushion and Asscher are considered fancy cut.
The cut of a diamond is considered to be the most important factor with respect to its beauty. The cut determines the brilliance of the diamonds – how light is reflected , dispersed and scintillated. Unlike color and clarity, there is not a single grade that defines it. Furthermore, two diamonds equal in carat weight, color and clarity can differ in appearance and value because of differences in cut quality.
The cut is the most complicated of the 4Cs. Unlike carat weight, color and clarity, whose value and rarity are related to the diamond’s natural formation, cut quality is the result of human decision and diamond cutting skills.
There are three factors that determine a diamond’s cut quality:
Proportions: the relative sizes and angles of the diamond’s parts and facets
Symmetry: the precision of the cut design, especially the facets
Polish: the smoothness and luster of the diamond’s surface
The cut grades are referenced on a diamond’s certificate often using the GIA standards of Excellent, Very Good, Good, Fair and Poor. For the most part, the actual measurements are mainly on the laboratory reports.
The quality of a diamond’s cut always speaks for itself.