---
title: "Proportions: meaning in gemology"
description: "A diamond's proportions are the angles and percentages that describe its shape in profile. They cover the table, crown, pavilion, star and lower half…"
url: https://digitalgemology.com/learn/glossary/proportions
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

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

# Proportions

Also called diamond proportions, make

A diamond's proportions are the angles and percentages that describe its shape in profile. They cover the table, crown, pavilion, star and lower half lengths, girdle, culet and total depth.

## In more detail

Each proportion is an angle or a percentage of the average diameter. So you can compare stones of any size directly. The proportions set how a stone handles light and most of its cut grade. Two values that are each in range can still lower the grade as a pair.

## On a grading report

On the proportion diagram of GIA and IGI reports.

## Related terms

- [Proportion diagram](https://digitalgemology.com/learn/glossary/proportion-diagram): The proportion diagram is a side-view profile of the stone, drawn to its measured proportions. It shows the table, depth, crown, pavilion, star and lower half lengths, girdle and culet.
- [Average diameter](https://digitalgemology.com/learn/glossary/average-diameter): The average diameter of a round is the mean of its minimum and maximum diameters, measured across the girdle.
- [Total depth](https://digitalgemology.com/learn/glossary/total-depth): Total depth is the height of a stone from table to culet as a percentage of its average diameter. It equals crown height + girdle thickness + pavilion depth.
- [Crown angle](https://digitalgemology.com/learn/glossary/crown-angle): The crown angle is the slope of the bezel facets, measured against the plane of the girdle.
- [Pavilion angle](https://digitalgemology.com/learn/glossary/pavilion-angle): The pavilion angle is the slope of the pavilion mains, measured against the plane of the girdle.
- [Cut grade](https://digitalgemology.com/learn/glossary/cut-grade): The cut grade rates how well a diamond's proportions and finish work, from Excellent to Poor. GIA gives it only to standard round brilliants in the D-to-Z color range.

## Learn more

- [How to read diamond proportions: decode a stone from its numbers](https://digitalgemology.com/learn/diamond-anatomy/how-to-read-diamond-proportions)
- [Diamond measurements explained: diameter, depth and percentages](https://digitalgemology.com/learn/diamond-anatomy/diamond-measurements-explained)
- [How to read the proportion diagram on a diamond report](https://digitalgemology.com/learn/grading-reports/diamond-proportion-diagram)

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