Diamond Culet & Diamond Girdle
A diamond’s culet is defined by the gem’s small pavilion. This point, commonly attributed to a diamond’s “base” area, is a focal point for a stone’s met facets. When a pavilion’s various faces meet, a majority of diamonds feature a uniformly-cut culet.
In many cases, proper angles are a result, and perfect points yield little to no culet. When this occurs, a culet is called “pointed”, due to its acute angle and minimal size. When a diamond’s pavilion facets don’t meet at this point, a diamond’s culet is rendered through a polished or rough facet.
Many diamonds feature a culet to exemplify the total number of facets. Pointed culets, however, do not contribute to this aesthetic. Culet is rated between “None” and “Extremely Large”. Once a loose diamond is examined for certification, it is placed—face up—for culet determination. Once the culet angle has been determined, sharp angles are immediately removed from the equation. They’re considered an extra facet.
While, historically, Old European cuts distinguished culets, they’re considered undesirable by modern standards. A diamond’s culets are visible from its table facet when viewed from above, large culets create a dark circle at a diamond’s bottom—diminishing its overall light capture.
A diamond’s girdle is its thin perimeter. The girdle divides the stone’s pavilion and crown, and it is see-able from a profile view. The girdle is a diamond’s widest area of circumference. When a loose diamond is measured for certification, their girdle is measured to fulfill width and length measurements. Girth is commonly measured in millimeters.
In most cases, a diamond’s girdle is polished, rough or faceted. Modern stone preparations feature faceted girdles—rather than round, bright girdles. Modern cuts also seek transparency in girdle cut, and steep cut diamonds utilize elongated facet rows as mirrors, revealing a polished, unfaceted girdle.
When girdles are rated, ratings from “Extremely Thin” to “Extremely Thick” are awarded. A diamond’s overall girdle measurements are derived from a stone’s thinnest and thickest areas. Once a rating is given, variance is derived to form the ending measurement.
Historically, a diamond’s girdle has never been a chief consideration. While important, a diamond’s girdle is a direct result from its symmetry, and overall shape is preferred to the measurement describing it. When analyzing a diamond’s girdle, experts use measurements tailored to its shape, so perceived size is always derived from relevant standards.