Diamond cut is the summary of a diamond's proportions evaluated using the attributes of brilliance, fire, and sparkle. While high marks of color or clarity affect a diamond, it's the cut that defines its proportions and ability to reflect light.
The Diamond cut scale is measured from Poor to Excellent. The Cut Grade of a diamond directly impacts its 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.
There are many factors that affect the brilliance of a diamond, the most important of which is its ability to reflect light:
When light enters the surface of a diamond, a portion of it is reflected back out of the table (top).
The remaining rays of light travel into the center of the diamond and bounce off its internal walls.
As light exits the diamond, dispersion causes the white light to be separated into multiple colors.
Why is a diamond's depth so important, and how is it determined? Diamond depth is the height of a diamond in millimeters measured from its table (top) to its culet (bottom). The depth percentage measures the ratio of a diamonds depth to its total width. Depth can significantly impact the quality of a diamond's cut and the amount of light it reflects.
A shallow cut diamond allows light to escape from its sides instead of reflecting off its top.
This premier cut style is well-proportioned and carefully angled to achieve a luminous appearance.
A diamond whose cut is too deep will look smaller than diamonds of similar carat weight.
Diamond polish and symmetry are critical components to cut quality. For maximum brilliance, every facet of a diamond should be polished after the cutting process. A symmetrical diamond will have well-balanced and properly aligned facets. If the facets are not symmetrical or not optimally shaped, they'll display less sparkle.
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. See also our Diamond Buying Guide Chart.
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.
Learn more about Diamond Table
This is the top portion of the diamond, located above the girdle and extending below the table.
Forming the outer edge of the diamond, this is where the crown and the pavilion meet and is the widest part of a diamond.
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.
Learn more about Diamond Girdle
Located at the bottom of the diamond, the pavilion bridges the girdle and the culet and form at the bottom (culet).
Located between the girdle and the culet (point), the pavilion is integral to the stone's light reflecting properties. A properly cut pavilion will allow the maximum amount of light to reflect from the surface of the stone. An excessively deep or shallow diamond can cause light to escape out of the bottom and sides, reducing its sparkle.
The smallest facet of a diamond, the culet is located at the very bottom of the stone. If the diamond ends in a point, the diamond grading report will show a value of 'None' for the culet designation. This small facet was originally intended to protect the diamond's pavilion, although today's settings are usually strong enough to render it unnecessary.
Learn more about Diamond Culet
Want the “too long, didn’t read” version of this article? Watch this short video to learn about diamond cut the fast way with the highlights about faceting, table and depth percentages, polish, and symmetry.
Still have questions? Contact a Diamond and Jewelry Expert at 866-737-0754 to start your diamond buying journey.