# ultramafic

> English word · Adjective · frequency rank #93,275

## Definitions
1. Describing igneous rocks that contain magnesium and iron and only a very small amount of silica, such as are found in the Earth’s mantle.

## Etymology
From ultra- + mafic.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/ultramafic