---
title: "Knife-edge girdle: meaning in gemology"
description: "A knife-edge girdle has no girdle band at all: the crown and the pavilion meet in a sharp line."
url: https://digitalgemology.com/learn/glossary/knife-edge-girdle
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

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[Glossary](https://digitalgemology.com/learn/glossary) · Anatomy and proportions

# Knife-edge girdle

Also called knife edge

A knife-edge girdle has no girdle band at all: the crown and the pavilion meet in a sharp line.

## In more detail

Tolkowsky's 1919 plan, our T57, has one. It saves weight but chips easily.

## On a grading report

Described as Extremely Thin on the proportion diagram.

## Related terms

- [Girdle](https://digitalgemology.com/learn/glossary/girdle): The girdle is the narrow band at the widest part of a cut stone, between the crown and the pavilion. It is the edge that a setting grips.
- [Girdle thickness](https://digitalgemology.com/learn/glossary/girdle-thickness): Girdle thickness is how thick the girdle is at its thinnest and thickest points. A report gives it as a range of words, such as "Thin to Medium".
- [Tolkowsky ideal cut](https://digitalgemology.com/learn/glossary/tolkowsky-ideal-cut): The Tolkowsky ideal cut is the round brilliant that Marcel Tolkowsky calculated in his 1919 book Diamond Design. It has a 40.75° (40° 45′) pavilion, a 34.5° (34° 30′) crown and a 53% table.
- [Girdle facets](https://digitalgemology.com/learn/glossary/girdle-facets): Girdle facets are the small facets cut around the girdle itself, such as the 16 on the T73.

## Learn more

- [Diamond girdle thickness: thin, medium, thick and what it costs you](https://digitalgemology.com/learn/diamond-anatomy/diamond-girdle-thickness)
- [The parts of a diamond: crown, girdle and pavilion](https://digitalgemology.com/learn/diamond-anatomy/parts-of-a-diamond)
- [Tolkowsky's 1919 ideal cut: the brilliant that was calculated](https://digitalgemology.com/learn/historic-cuts/tolkowsky-ideal-cut-1919)

[All 328 terms](https://digitalgemology.com/learn/glossary)