Education

GIA Education

Cut

A Diamond’s Cut Unleashes Its Light

A diamond’s cut grade is really about how well a diamond’s facets interact with light. The diamond’s cut is crucial to the stone’s final beauty and value.

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.

If a diamond is cut too shallow or too deep light will escape from the side of the stone or leak out of the bottom. A well-cut diamond will direct more light through the crown.

GIA Cut grade scale consists of 5 grades ranging from Excellent to Poor.

Color

The color evaluation of most gem-quality diamonds is based on the absence of color.

GIA’s D-to-Z color-grading scale is the industry’s most widely accepted grading system. The scale begins with the letter D, representing colorless, and continues, with increasing presence of color, to the letter Z.

Many of these color distinctions are so subtle that they are invisible to the untrained eye; however, these distinctions make a very big difference in diamond quality and price.

Clarity

Natural diamonds are the result of carbon exposed to tremendous heat and pressure deep in the earth. This process can result in a variety of internal characteristics called ‘inclusions’ and external characteristics called ‘blemishes.’

Evaluating diamond clarity involves determining the number, size, relief, nature, and position of these characteristics, as well as how these affect the overall appearance of the stone. While no diamond is perfectly pure, the closer it comes, the higher its value.

Carat

Diamond Carat Weight Measures a Diamond’s Apparent Size

All else being equal, diamond price increases with diamond carat weight because larger diamonds are rarer and more desirable. But two diamonds of equal carat weight can have very different values (and prices) depending on three other factors of the diamond 4Cs: Clarity, Color, and Cut.