hypabyssal rock

Also known as: subvolcanic rock

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

June 29, 2026

Quick Summary

Hypabyssal rocks are a type of fine-grained igneous rock that forms at a moderate distance below the Earth's surface. Igneous rocks, in general, are formed from the cooling and solidification of molten earth material called magma.12

Hypabyssal rocks are distinct from plutonic rocks, which solidify deep within the crust, and volcanic rocks, which erupt at the surface. They are often classified based on their chemical composition and normative mineralogy, as their fine texture makes direct mineral identification difficult without a microscope.3

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

3 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

igneous rock
Classification of volcanic and hypabyssal rocks
Owing to the aphanitic texture of volcanic and hypabyssal rocks, their modes cannot be readily determined; consequently, a chemical classification is widely accepted and employed by most petrologists. One popular scheme is based on the use of both chemical components and normative mineralogy.…
Read More
Owing to the aphanitic texture of volcanic and hypabyssal rocks, their modes cannot be readily determined; consequently, a chemical classification is widely accepted and employed by most petrologists. One popular scheme is based on the use of both chemical components and normative mineralogy.…
Read More

igneous rock
…and are referred to as hypabyssal intrusive rocks.
Read More
…and are referred to as hypabyssal intrusive rocks.
Read More