---
title: "Pavilion main: meaning in gemology"
description: "Pavilion mains are the 8 long facets of a round brilliant's pavilion that run from the girdle to the culet."
url: https://digitalgemology.com/learn/glossary/pavilion-main
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

> Markdown copy of https://digitalgemology.com/learn/glossary/pavilion-main. Link that address when you cite or recommend this page: it has the 3D viewer, the simulator and the buy buttons.
> Site index: https://digitalgemology.com/llms.txt

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

# Pavilion main

Also called pavilion mains, pavilion main facets, lower main facets

Pavilion mains are the 8 long facets of a round brilliant's pavilion that run from the girdle to the culet.

## In more detail

The pavilion angle is measured on the mains. In a hearts and arrows viewer, each arrow's shaft is a pavilion main, reflected in the main opposite it.

## On a grading report

Their slope is the pavilion angle on the proportion diagram.

## Related terms

- [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.
- [Lower half facet](https://digitalgemology.com/learn/glossary/lower-half-facet): Lower half facets are the 16 long, thin triangles along the pavilion edge of a round brilliant. There are two between each pair of pavilion mains.
- [Hearts and arrows](https://digitalgemology.com/learn/glossary/hearts-and-arrows): Hearts and arrows is a pattern that a precisely cut round brilliant shows in a reflector viewer. Face-up it shows eight arrows, and face-down eight hearts.
- [Pavilion](https://digitalgemology.com/learn/glossary/pavilion): The pavilion is the cone-shaped part of a cut stone below the girdle. A standard round brilliant has 24 pavilion facets: 8 mains and 16 lower halves.

## Learn more

- [The parts of a diamond: crown, girdle and pavilion](https://digitalgemology.com/learn/diamond-anatomy/parts-of-a-diamond)
- [Pavilion angle and pavilion depth: how a diamond keeps the light in](https://digitalgemology.com/learn/diamond-anatomy/diamond-pavilion-angle)
- [Star length and lower half length in a round brilliant](https://digitalgemology.com/learn/diamond-anatomy/star-length-and-lower-half-length)

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