Diamond girdle may not be on most people's priority list when looking for diamonds, but it is an important element of the overall quality of a stone. The girdle affects not only the beauty but also the structural and practical aspects of the stone. For this reason, diamond girdle is a quite important feature.
Where is the Diamond Girdle?
The girdle refers to the part of the diamond that separates the crown from the pavilion. The girdle is made up of the outermost facet of the widest part of the stone. When mounted into jewelry, the girdle is attached to the setting. If you want to accurately measure the length and width of the loose diamond, you must measure the girdle.
How is the Girdle Graded?
The girdle of the diamond makes up one aspect of its cut and is measured and included in the grading report.
Because the girdle is not always the same width around the diamond, the stone is measured at several different points and then given two ratings based on its thickest and thinnest.
However, if the stone measurements are the same at different points, then a single girdle rating is given. The diamond chart below shows the difference.
Like the other features of diamond, the girdle is also graded on a scale. Here is the industry's accepted scale:
Extremely Thin - the girdle is almost non-existent. It is fragile and may chip or break. It needs to be carefully installed into the Settings. The depth of the diamond may be shallow and the cut grade may be affected.
Very Thin - The waist is very thin and must be set carefully. There is fragmentation and breaking.
Thin/Medium - this is the best ratio. Fracture risk is low and does not affect the cutting grade. Good diamond depth.
Slightly Thick - perfect for ideal ratio, low risk chisel. Cut grade will not be negatively affected.
Very Thick - very thick waistline, will affect cut grade. The diamond may be too deep.
Extremely Thick - Too thick at the waist can make a diamond look smaller. It was much thicker than expected.
The perfect belt is medium to slightly chunky, as these ratios balance durability with aesthetics and practicality.
Types of Girdles
There are a few different girdle variations, mostly depending on the shape of the diamond:
Faceted Girdle – You’ll see faceted girdles on beautifully cut diamonds as they enhance the glitter and help the diamond's luminous performance. These facets are typically triangular in shape.
Polished Girdle – This type of girdles is typically seen on step cut diamonds such as emerald or asscher cut diamonds. Polished girdles are not faceted and fit in with the rest of the facets of step cuts – long, open and transparent.
Rough Girdle – Also known as bruted or frosted, this type of girdle is a rough, unpolished style which gives the girdle a frosted glass look. This type of girdle is not common and while it adds a textured look to the diamond, it tends to reduce brilliance.
Today almost all diamond girdles are either faceted or polished.
How the Girdle Impacts the Diamond?
The girdle affects the symmetry of the diamond. If the girdle is too thin or too thick, it will make the diamond look unbalanced.
A too thin girdle compromises the strength and durability of the diamond as it can break when mounting the diamond. Setting the diamond requires pressure and heat, which is too much for a thin girdle. A setting like bezel or halo will protect the diamond while wearing it. This will protect it from impact and protect the knife-edge of the stone.
A too thick girdle, on the other hand, will have a lot of wasted diamond in the middle and will make the stone look smaller than it really is. While it may not affect the light performance of the stone, thick girdle affects the apparent size.
In some cases, a thick girdle is useful, especially for a diamond-shaped prong like marquise or pear. If the girdle is thicker at this point, it strengthens the area reducing the likelihood of the diamond chipping.
Sometimes a diamond’s girdle is thickened simply to retain any rough that would be wasted anyway. This makes economic sense because it makes the diamond heavier, which then corresponds to a higher carat weight. And as we all know, higher carat weight means a more expensive diamond.
An undesirable girdle width can affect the price and quality of the diamond, which can offer good value for you. Depending on the setting, the girdle may not be visible at all, in which case paying less for a very thin or very thick girdle can be an excellent option.
Overall, if the diamond is cut to ideal specifications, the width of the girdle shouldn’t affect the stone’s light performance or cut quality.
Post time: Feb-14-2023