Diamond Cuts

This guide explores how to assess diamond grades according to the industry standards in cut, color, clarity, and carat.

What is Diamond Cut?

As one of the 4 C’s used to describe and determine diamond quality, cut references how well a diamond’s facets interact with light. Though it’s often confused with shape, which refers to the external outline of a diamond (such as round, oval, or pear), cut is actually responsible for a diamond’s ability to transmit light and sparkle. Precise artistry and craftsmanship are required to cut a diamond so that its proportions, symmetry, and polish deliver maximum light return and stunning shine. The better a diamond is cut, the more sparkly it will be.
table (1)
Fair
Good quality cut which reflects some light while maximizing weight. While not as brilliant as a good cut, still a quality diamond.
Good
Premium quality cut to optimize the size without sacrificing quality or beauty. Reflects most light that enters.
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Very Good
Superior quality cut that reflects nearly as much light as the ideal cut while at a substantially lower cost.
Ideal
Exquisite quality cut to create the optimal combination of brilliance and fire. Reflects nearly all light that enters the diamond.
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Super Ideal
Cut to the most exacting standards. These diamonds have the most desirable dimensions and are proportioned to return the maximum possible light.

Cut is a crucial factor to consider when selecting a diamond, as it is accountable for its sparkle. An excellently cut diamond will deliver the classic, unmistakable light show you expect from a diamond. A poorly cut diamond, on the other hand, will be much duller. As cut can significantly impact the appearance of a diamond and the light it emits, it’s essential to understand what it is and how it’s graded.

The Gemological Institute of America (GIA) has extensively studied how light interacts with round brilliant cut diamonds to better understand the factors that contribute to their appearance and sparkle. The result of their studies was the GIA Cut Grading System, which standardizes and evaluates cut quality on appearance (brilliance, fire, scintillation), design (proportion), and craftsmanship (polish, symmetry). Their cut scale ranges from Excellent to Very Good, Good, Fair, and Poor. 

Most independent institutes use their own language to rank the overall cut of a diamond. For example, the International Gemological Institute (IGI) adds an extra rank atop Excellent, rating their highest-quality diamonds as Ideal. At Brilliant Earth, we also use specific scale language to help our customers understand subtle cut differences affecting quality and price. We base our scale on the cut specifications the certifying gemological laboratory provides and rank diamonds from Super Ideal to Ideal, Very Good, Good, Fair, and Poor. This means that, for example, a GIA-certified diamond with an Excellent cut grade will be listed as a Super Ideal or Ideal diamond on the Brilliant Earth site.

Cut Characteristics

To best understand the cut grade of a diamond, it's important to understand the following characteristics that, when evaluated together, define a high-quality cut.

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Table

The flat surface at the top of the diamond.

 
crown
Crown

The top portion of a diamond, from the girdle to the table.

 
girdle
Girdle

The flat surface at the top of the diamond.

 
pavilion
Pavilion

The top portion of a diamond, from the girdle to the table.

 
culet
Culet

The flat surface at the top of the diamond.

 
depth
Depth

The flat surface at the top of the diamond.

 

Polish

Polish is the quality of a diamond’s external surface condition as a result of the polishing process. Various features, such as pits or nicks, are considered in evaluating polish. It is graded on a scale ranging from Ideal or Excellent to Poor and is generally listed on a diamond certificate.

Polish

Polish is the quality of a diamond’s external surface condition as a result of the polishing process. Various features, such as pits or nicks, are considered in evaluating polish. It is graded on a scale ranging from Ideal or Excellent to Poor and is generally listed on a diamond certificate.

Polish

Polish is the quality of a diamond’s external surface condition as a result of the polishing process. Various features, such as pits or nicks, are considered in evaluating polish. It is graded on a scale ranging from Ideal or Excellent to Poor and is generally listed on a diamond certificate.

Polish

Polish is the quality of a diamond’s external surface condition as a result of the polishing process. Various features, such as pits or nicks, are considered in evaluating polish. It is graded on a scale ranging from Ideal or Excellent to Poor and is generally listed on a diamond certificate.
Now that you understand the characteristics considered when a professional determines a cut grade let’s explore the Brilliant Earth scale to help you pick the perfect diamond.

Polish

Now that you understand the characteristics considered when a professional determines a cut grade let’s explore the Brilliant Earth scale to help you pick the perfect diamond.

Polish

Now that you understand the characteristics considered when a professional determines a cut grade let’s explore the Brilliant Earth scale to help you pick the perfect diamond.

Polish

Now that you understand the characteristics considered when a professional determines a cut grade let’s explore the Brilliant Earth scale to help you pick the perfect diamond.

The Gemological Institute of America (GIA) has extensively studied how light interacts with round brilliant cut diamonds to better understand the factors that contribute to their appearance and sparkle. The result of their studies was the GIA Cut Grading System, which standardizes and evaluates cut quality on appearance (brilliance, fire, scintillation), design (proportion), and craftsmanship (polish, symmetry). Their cut scale ranges from Excellent to Very Good, Good, Fair, and Poor. 

Most independent institutes use their own language to rank the overall cut of a diamond. For example, the International Gemological Institute (IGI) adds an extra rank atop Excellent, rating their highest-quality diamonds as Ideal. At Brilliant Earth, we also use specific scale language to help our customers understand subtle cut differences affecting quality and price. We base our scale on the cut specifications the certifying gemological laboratory provides and rank diamonds from Super Ideal to Ideal, Very Good, Good, Fair, and Poor. This means that, for example, a GIA-certified diamond with an Excellent cut grade will be listed as a Super Ideal or Ideal diamond on the Brilliant Earth site.

Polish

Now that you understand the characteristics considered when a professional determines a cut grade let’s explore the Brilliant Earth scale to help you pick the perfect diamond.
Now that you understand the characteristics considered when a professional determines a cut grade let’s explore the Brilliant Earth scale to help you pick the perfect diamond.

Polish

Now that you understand the characteristics considered when a professional determines a cut grade let’s explore the Brilliant Earth scale to help you pick the perfect diamond.

Polish

Now that you understand the characteristics considered when a professional determines a cut grade let’s explore the Brilliant Earth scale to help you pick the perfect diamond.

Polish

Now that you understand the characteristics considered when a professional determines a cut grade let’s explore the Brilliant Earth scale to help you pick the perfect diamond.

Diamond Cut FAQ's

What's the difference between diamond cut and diamond shape?

Diamond cut and diamond shape are not the same thing. Diamond shape refers to the external outline of a diamond (round, oval, or marquise, for example). Diamond cut refers to the precision and artistry used to craft a diamond’s internal faceting and, therefore, brilliant sparkle. While both shape and cut are critical factors to consider when picking the perfect diamond, we suggest first deciding on the shape and then finding a diamond that balances the 4 C’s of cut, color, carat, and clarity with your budget.

What's the difference between diamond cut and diamond shape?

Diamond cut and diamond shape are not the same thing. Diamond shape refers to the external outline of a diamond (round, oval, or marquise, for example). Diamond cut refers to the precision and artistry used to craft a diamond’s internal faceting and, therefore, brilliant sparkle. While both shape and cut are critical factors to consider when picking the perfect diamond, we suggest first deciding on the shape and then finding a diamond that balances the 4 C’s of cut, color, carat, and clarity with your budget.

What's the difference between diamond cut and diamond shape?

Diamond cut and diamond shape are not the same thing. Diamond shape refers to the external outline of a diamond (round, oval, or marquise, for example). Diamond cut refers to the precision and artistry used to craft a diamond’s internal faceting and, therefore, brilliant sparkle. While both shape and cut are critical factors to consider when picking the perfect diamond, we suggest first deciding on the shape and then finding a diamond that balances the 4 C’s of cut, color, carat, and clarity with your budget.

What's the difference between diamond cut and diamond shape?

Diamond cut and diamond shape are not the same thing. Diamond shape refers to the external outline of a diamond (round, oval, or marquise, for example). Diamond cut refers to the precision and artistry used to craft a diamond’s internal faceting and, therefore, brilliant sparkle. While both shape and cut are critical factors to consider when picking the perfect diamond, we suggest first deciding on the shape and then finding a diamond that balances the 4 C’s of cut, color, carat, and clarity with your budget.

What's the difference between diamond cut and diamond shape?

Diamond cut and diamond shape are not the same thing. Diamond shape refers to the external outline of a diamond (round, oval, or marquise, for example). Diamond cut refers to the precision and artistry used to craft a diamond’s internal faceting and, therefore, brilliant sparkle. While both shape and cut are critical factors to consider when picking the perfect diamond, we suggest first deciding on the shape and then finding a diamond that balances the 4 C’s of cut, color, carat, and clarity with your budget.