Girdle
The girdle is the thin band around a diamond's widest point, where the crown above meets the pavilion below.
The girdle is the narrow band that runs around a diamond at its widest point, separating the crown above from the pavilion below. It is where a setting's prongs usually grip the stone. Its thickness is graded from extremely thin to extremely thick, and it affects both durability and how the diamond's weight is distributed.
Thickness, durability and hidden weight
GIA grades girdle thickness on a scale from extremely thin through thin, medium, slightly thick, thick and up to extremely thick. A girdle that is too thin is fragile and can chip on impact, while one that is too thick adds weight without adding visible size, so you pay for carats that hide in the rim rather than show face-up. A medium to slightly thick girdle is a common, safe range.
The girdle finish also varies. It can be bruted to a slightly rough grey surface, polished smooth, or faceted with small facets around the edge. Many reports note the finish, and a laser-inscribed report number often sits on the girdle where it does not affect appearance.
- Graded extremely thin to extremely thick
- Too thin chips easily, too thick hides weight
- Medium to slightly thick is a safe range
- Often bruted, polished or faceted, and may carry the laser inscription
Why it factors into cut and value
Because girdle thickness affects durability and weight distribution, GIA includes it in the cut grade for round brilliants. From a value angle, an overly thick girdle means some of the carat weight you paid for is buried in the rim rather than contributing to the diamond's spread, so two stones of equal weight can look different sizes depending on their girdles.
- The girdle is the thin band at a diamond's widest point.
- It separates the crown from the pavilion and is where prongs grip.
- It is graded from extremely thin to extremely thick.
- Too thin risks chipping, too thick hides weight you paid for.
- It factors into the cut grade and may carry the laser inscription.
Girdle, in short.
What girdle thickness is best?
A medium to slightly thick girdle is a safe range. Extremely thin girdles risk chipping, and extremely thick ones hide weight in the rim without adding visible size.
Why is my diamond's report number on the girdle?
Many labs laser-inscribe the report number on the girdle because it is out of sight when set and does not affect appearance. It lets you match the physical stone to its grading report.
Related terms
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