Diamond Cut

One of the most defining characteristics of a diamond is its cut. While high grades of color, clarity, and carat weight affect a diamond, it's the cut that determines the symmetry of the stone's facets, its overall proportions, and its ability to reflect light.

An expertly-cut diamond will achieve high levels of brilliance, sparkle, and durability. Even if a diamond is graded well in other areas, a poor cut can result in a dull, muted effect.

Cuts of Diamonds

Learn more about each diamond shape, its unique traits, aesthetic properties, and markings of quality Diamond Shape.

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Parts of a Diamond

A diamond is comprised of five main parts that affect its shape and radiance. Knowing these terms will help you understand the important components to consider when selecting a diamond.

Click the orange arrows to go through each term.
Table
The largest facet of the diamond, a table is the flat surface on the top of the stone, resembling a 'table'.
Crown
This is the top portion of the diamond, located above the girdle and extending below the table.
Girdle
Forming the outer edge of the diamond, this is where the crown and the pavilion meet and is the widest part of a diamond.
Pavilion
Located at the bottom of the diamond, the pavilion bridges the girdle and the culet and form at the bottom (culet).
Culet
The smallest facet of a diamond, the culet is located at the very bottom of the stone.

Light's Effect on a Diamond

There are many factors that affect a diamond’s brilliance, the most important of which is its ability to reflect light. As a diamond passes through a light source, tiny flashes will be visible within the stone.

Click the orange arrows to go through each term.
Table reflection
When light enters the surface of a diamond, a portion of it is reflected back out of the table (top)
Refraction
The remaining rays of light travel into the center of the diamond and bounce off its internal walls, an effect known as refraction.
Dispersion
As light exits the diamond, dispersion causes the white light to be separated into multiple colors. Some light will escape out the bottom and sides, and some will reflect out of the top of the stone. The light that is reflected is referred to as the 'fire' of the diamond.

Diamond Cut and Depth

The cut of a diamond determines how much light is reflected back to the wearer, directly impacting its brilliance and fire. Diamonds are generally categorized into three main types of cuts:

Click the orange arrows to go through each term.
Shallow Cut
Although a shallow cut diamond will create the illusion of a larger stone, it allows light to escape out the sides instead of reflecting off the top, creating a lack of brilliance and sparkle.
Ideal Cut
If you're seeking a high quality diamond that beautifully reflects light, this is the cut for you. This premier cut style is well-proportioned and carefully angled to achieve a luminous appearance.
Deep Cut
This type of cut poorly reflects light, resulting in a dull, muted appearance.

Diamond Cut Terminology to Consider

A diamond's cut is an integral factor in determining its brilliance and fire. Even a flawless diamond will appear dull and muted if the cut is poor. When evaluating the cut of a diamond, there are some core characteristics and terminology that should be known:

Depth & Depth Percentage
A diamond's depth can be determined by measuring the entire stone's height from the table to the culet and is described in millimeters. The depth percentage measures the ratio of the stone's depth (from the table to the culet) to the diamond's total diameter. To learn about the ideal depth percentage for each diamond shape, visit our Diamond Shape page.
Table & Table Percentage
A diamond's table is the largest facet of the stone, comprising the flat surface on the top. The table percentage is the ratio of the width of the diamond's top facet in relation to the width of the entire stone. The right ratio results in a large amount of fire and brilliance. To learn about the ideal table percentage for each diamond shape, visit our Diamond Shape page.
Measurements
Measured in millimeters, the measurements of a diamond's length, width, and height are used to evaluate the symmetry and quality of its cut.
Proportions
A diamond's proportions, a measure of the number and size of facets and its overall length and width, are integral in determining the quality of its cut. When a diamond is cut with the ideal proportions for its shape, it will reflect more light out of the top, resulting in higher levels of fire and brilliance. A poorly cut diamond with incongruous proportions will allow light to escape out the bottom and sides, resulting in a dull, dark appearance.
Crown
A diamond's crown extends from the top of the stone (the 'table') down to the girdle (the widest point of the diamond). Crowns can be comprised of step cut facets or brilliant cut facets.
Girdle
This is the portion of the diamond between the crown and the pavilion, essentially spanning the width of the stone from side to side. The measurement of the girdle represents the perimeter of the diamond. A diamond's girdle can be rough, polished, or faceted, and does not typically affect the quality or appearance of the stone.
Pavilion
This is the portion of the diamond between the crown and the pavilion, essentially spanning the width of the stone from side to side. The measurement of the girdle represents the perimeter of the diamond. A diamond's girdle can be rough, polished, or faceted, and does not typically affect the quality or appearance of the stone.
Culet
This is the portion of the diamond between the crown and the pavilion, essentially spanning the width of the stone from side to side. The measurement of the girdle represents the perimeter of the diamond. A diamond's girdle can be rough, polished, or faceted, and does not typically affect the quality or appearance of the stone.

Diamond Faceting

With modern diamond-cutting techniques, there are two common methods of cutting facets, each with its own unique, light-reflecting properties:

Step Cut Faceting

In this approach, the facets are elongated and placed in rows to simulate a mirrored staircase.

Brilliant Cut Faceting

This technique creates triangular-shaped facets that face outwards from the center of the diamond.

Polish, Symmetry & Cut Grade

A diamond's polish and symmetry are critical to the quality of its cut. For maximum brilliance, every facet of a diamond should be professionally polished after the cutting process. A high quality polish will leave little to no scratches and marks, while a poor polish can result in imperfections on the surface of the diamond, which can lower its value.

A symmetrical diamond will have well-balanced, properly aligned facets, resulting in a high level of fire and brilliance. If the facets are not symmetrical or not optimally shaped, they'll display less sparkle.

A gemologist assigns a cut grade as a means of measuring a diamond's proportions, craftsmanship, quality of polish, and light reflecting properties. A diamond with a high quality cut grade will exude a large amount of brilliance and fire.

A diamond's ratings for symmetry, polish, and cut grade may vary based on which Gemological Laboratory is evaluating it, as each agency uses a different scale. To learn more, visit our Diamond Certification page.

Guidance & Advice

The cut quality of a diamond can vary depending on the stone’s shape. To learn about each diamond shape, please visit our Diamond Shape page.

Diamond Cut & Value

The quality of a diamond's cut has a significant impact on its value. A well cut stone sacrifices more of the rough diamond during the cutting process, resulting in a higher market value. It will, however, exhibit better light reflecting properties, exuding greater fire and brilliance. Improperly cut diamonds will have less visual appeal and a decreased value. To ensure the best value, look for a certified diamond with polish and symmetry ratings of 'Good' or better.

Brilliance Diamond Make

Not all certification labs offer a “Cut” on their certificates especially when it comes to fancy shaped diamonds (non-round cuts). Understanding that this is a crucial factor when purchasing a diamond, Brilliance gives its own rating on a diamond called a “Diamond Make or Cut”. Combining all the different factors that are important in a diamond cut, “Make” is a term used to describe the overall appearance of a diamond and is based on a combined analysis of its shape, cut, proportions, polish, symmetry, and light reflecting properties. The “Make” of a diamond directly impacts its brilliance and beauty; if a diamond is designed, cut, and finished properly, it will have a much more desirable appearance, even when compared to diamonds of higher color and clarity grades. Brilliance gemologists use this term to provide our customers with a general assessment of cut to simplify shopping for the perfect loose diamond.

We use the following designations to rate the 'Make' of our diamonds:

Super Ideal Make
Our highest quality cut, this Make will reflect the maximum amount of light, exhibiting unrivaled brilliance and fire. 'Super Ideal' Make diamonds are extremely rare; only 5% of our loose diamond assortment receives this grade.
Ideal Make
This indicates a superior level of craftsmanship, emitting the most brilliance and light. Consumers seeking premium cuts prefer 'Ideal' Make diamonds.
Excellent Make
Cut to a high-quality polish and symmetry, this diamond Make will reflect all light as brilliance and fire.
Very Good Make
This grade of diamond reflects nearly all light that enters. Less expensive than an 'Excellent' Make, it still displays a good amount of brilliance and sparkle.
Good Make
An economical choice for the diamond shopper on a limited budget, a 'Good' Make reflects most light that enters it, offering beauty at an attractive value.