All You Need to Know About a Diamond Culet

Culet Scale

The culet of a diamond, even its pointed end, is assessed and graded on a scale. The grading involves evaluating the point where the diamond closes under the pavilion at 10x magnification. The culet grade indicates the size and visibility of the opening under the pavilion. Culet significantly impacts a diamond’s light performance and light leakage, thereby affecting its cut grade.

None: This type of culet has no opening under the pavilion, ensuring that light is fully reflected back into the diamond, which is a requirement for diamonds aiming for an excellent cut grade.

Very Small: The culet has a tiny, barely visible opening that does not affect the diamond’s sparkle or light performance significantly.

Small: The culet features an open under magnification, allowing a small amount of light leakage, though it does not heavily impact the brilliance and sparkle of the diamond.

Medium: This culet has a more noticeable opening that leads to light loss, affecting the diamond’s light performance as light escapes through the center of the pavilion.

Large: An easily visible opening in the culet acts like a facet, causing light leakage and affecting the diamond’s brilliance. Large culets are typically found in Old European and Old Mine cut diamonds.

Very Large: With a notably large opening, this culet type is not found in modern brilliant cuts and is seen more in diamonds with cuts like Old Mine and Old European.

How Culet Grade is Determined

GIA graders inspect a diamond face-up and under 10x magnification, viewing it through the table facet. They assign a culet grade based on its appearance compared to the other facets of the diamond. If the diamond lacks a culet facet, it is designated as None. Clarity imperfections in the culet are also taken into consideration when grading. Graders utilize magnification and photographic references to ensure precise culet grading.

The Influence of Culet on a Diamond

The culet, located at the point where the pavilion closes under the diamond, significantly affects its light performance. Larger or open culets can lead to light leakage from the pavilion, while closed or None graded culets ensure proper light reflection. Modern fancy shapes and brilliant cut diamonds today mostly feature closed or None culets due to advancements in cutting precision. Culet importance is often underestimated as closed or None culets are favored for better light performance, whereas open culets are more common in antique-style diamonds like Old European and Old Miner cuts.

Due to its pointed and vulnerable nature, a culet can be damaged by high-impact or hard contact. However, when set in jewelry, it is safeguarded and less likely to incur damage. A chipped culet is noticeable as it is situated directly below the diamond’s table.