What Is The Girdle Of A Diamond?

by Ultimate Jewelry Guide
What Is The Girdle Of A Diamond?

The expertise that goes into creating a faceted gemstone from a raw diamond is something to be treasured. An expert diamond cutter will examine the rough stone and determine how to complete the girdle, independent of whether the diamond is a brilliant cut or a step cut while planning the optimum cut for a diamond. But what is the diamond of a girdle, and how does it affect your diamond?

What Is The Girdle?

The girdle of a diamond is simply the narrow perimeter of a diamond that separates the crown from the pavilion. The girdle is the broadest part (or circumference) of the polished diamond when viewed in its setting or from a profile view – the region of the stone that makes contact with the setting itself. When measuring loose diamonds, the girdle is used to determine length and width in millimeters.

The girdle of a diamond can be rough, polished, or faceted. Brilliant cut diamonds (those with triangular-shaped facets) frequently have a faceted girdle rather than a full-round girdle, which increases the transparency of the stone. The girdles of step-cut diamonds (with rows of elongated facets) are normally polished and not faceted.

Types Of Diamond Girdles

Here’s a more detailed explanation of the three sorts of girdles and how they affect your diamond:

Rough Girdle

Most brilliant cut diamonds had rough girdles a few decades ago, where the girdles were left natural and unpolished. After being shaped by another rough diamond, the girdle developed a “frosty” aspect. The girdle of the diamond will appear icy, white, grainy, rough, and opaque when examined through a jeweler’s loupe. Because it resembles a man’s beard, the rough girdle is commonly referred to as a “bearded girdle.”

Polished Girdle

A polished girdle means that the diamond’s entire outer edge has been polished into a single, clear facet. This procedure allows you to see straight through the diamond. The girdle’s entire surface area is smooth and clean all the way around; there are no facets or traces of roughness, just a smooth strip that runs around the diamond’s perimeter.

Faceted Girdle

A faceted girdle, like the rest of the diamond, is cut and polished. The faceted girdle is the most typical finishing on a diamond with a more modern design. A faceted girdle, like the rest of the diamond, is cut and polished with a sequence of well-proportioned vertical facets. However, what does having a faceted girdle imply? Small facets are cut and polished along the outside edge of the faceted girdle during development, removing microscopic feathers generated during the bruting process. Because it reflects light and blends in with the rest of the diamond, the faceted girdle is practically imperceptible.

Bearded Girdle

A Girdle with Hairline Chips or Feathers around the Outside Edge of the Diamond is known as a Bearded Girdle. These flaws appear where the Girdle joins the Crown (Diamond’s Top) or where the Pavilion meets the Girdle (Base of the Diamond). When a rough diamond is cut and polished, it goes through a series of stages that include faceting and proportioning. A Bearded Girdle might result if the cutting or bruting process is done too quickly or too sloppily.

Diamond Girdle Ratings

When a diamond is rated, its thickest and thinnest points are measured at various positions along the girdle.

A single rating is provided if both points fall into the same category. The girdle is typically evaluated as a range, such as ‘Very Thin to Thick,’ to account for the difference in thickness between the thickest and thinnest areas.

Extremely Thin Girdles

Super Thin Girdles are an extremely fine (and difficult to discern) line that runs around the Diamond and can easily chip or break. To observe these Girdles, you’ll probably need a microscope. Girdles this thin aren’t going to last too long!

Very Thin Girdles

Incredibly Thin Girdles are fine lines that separate the top and bottom facets. They are nonetheless susceptible to chipping and shattering. The Girdle may require 10x magnification to be seen in detail.

Thin Girdles

Small lines that circle the stone are known as thin girdles. Thin Girdles are wonderful for Diamonds because they’re still small enough to chip if you’re not careful. To see them clearly, you’ll probably need 10x magnification.

Medium Girdles

The Girdle Grades of Medium Girdles are in the center. They’re neither too thick nor too thin (just right). Medium Girdles provide a good edge for protection and prong gripping. A Medium Girdle will be noticeable, but it will not be overpowering or distracting. They contribute to the stone’s symmetry and flow.

Slightly Thick Girdles

Despite their thickness, they are still an excellent Girdle to have. A Slightly Thick Girdle does not detract from the appearance or feel of the stone while still providing excellent protection and making holding easier.

Thick Girdles

Thick Girdles are a little more daring. When viewed from the side, they can become a touch overly fat in the middle, which can be more conspicuous and obvious. Even from a slightly slanted face-up position, they may stick out.

Very Thick Girdles

In a crowd, Very Thick Girdles will stand out. From most perspectives, a thick girdle is distracting and visible even without magnification. You won’t be able to miss this Girdle!

Extremely Thick Girdles

Girdles that are excessively bulky and unsightly are a bad idea. They consume far too much Carat Weight, disrupting the stone’s symmetry and proportions. When looking at the stone from the top-down, these Girdles may appear as frozen circles around the table. They’re colossal and obnoxious! Extremely Thick Girdles are a no-no in my book!

How Is The Girdle Of A Diamond Graded?

The thickest and thinnest parts of the diamond girdle are used to determine the girdle grade. The diamond’s girdle is graded using a piece of optical measuring equipment or a microscope. The measures can be expressed as a percentage of the diamond’s average diameter. The final grade is determined by visually inspecting the girdle and its shape. The grade is determined by looking at the girdle both straight on and at an angle.

Below is a list of Components that are considered in grading diamonds.

Diamond Light Performance


When seeing a diamond, the viewer’s head and body, the surrounding surroundings, and variable lighting can cause contrast, which is the difference in brightness between two points. When contrasting facets are present, the eye finds them more appealing than when they are all the same.


A diamond’s capacity to reflect the light it receives from above. Brightness with a positive contrast is defined as brilliance.


The perception of fire is created by dispersion, which is heightened by various light sources (e.g., spotlights in a jewelry store’s ceiling or a conference center’s ceiling) and lessened by broad diffused light (i.e., fluorescent light fixture).


The amount of light reflected out the top of a diamond is reduced when light seeps out the sides or bottom.

Diamond Proportion Factors


The girdle of a diamond is visible at the table’s edge when seen at a sufficient angle. To guarantee that an acceptable tilt angle is reached, a minimum pavilion angle is computed for each table percentage.


For girdles classified as extremely thin and very thin, the cut grade is lowered. Damage is also more likely in diamonds with crown angles less than 30 degrees.

Weight Ratio

The “spread” of a diamond refers to its size in relation to its weight. The majority of diamond buyers are looking for the greatest millimeter size that weighs the least amount of money while yet providing excellent light performance.

Girdle Thickness

In the past, grading laboratories in the United States measured the thickness of the girdle at its narrowest point or “valley.” The new AGS cut grade system now assesses girdle thickness at the thickest region of the girdle, referred to as the “peak.”

What Are The Diamond Girdle Effects?

When setting or wearing a diamond with an exceedingly thin girdle, there is a tiny chance of chipping along the girdle edge. The diamond should be well-secured within the setting to avoid contact with harsh or abrasive surfaces for the best protection. As long as the diamond is cut to correct proportions, a diamond with an extraordinarily thick girdle will have a lot of brightness and fire. A diamond with an extraordinarily thick girdle, on the other hand, concentrates its weight in the middle, making it appear smaller from the top than a diamond with a thinner girdle.

When assessing the influence of an excessively thick girdle on a diamond, it’s crucial to consider the stone’s entire dimensions. The exceptionally thick girdle will not have a substantial impact on the perceived size if the measurements are within the optimal range.

Diamonds with unusually thick or thin girdle ratings are sometimes less expensive than equivalent diamonds with excellent girdle ratings, giving the consumer a wonderful deal. 

Should You Consider Your Diamonds Girdle?

Finally, while girdle style is determined by personal desire, the size of your girdle should be considered before selecting a diamond. The girdle thickness for your diamond can be ideal or utterly wrong, resulting in a stone with poor proportion and symmetry. As a result, always check the diamond certificate to see what it says about the girdle. Look for a cut grade of at least ‘Very Good,’ and aim to stay within the thin to medium thickness range.

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