ABCTE Master of Science in Education (MSE) Practice Exam 2026 - Free MSE Practice Questions and Study Guide

The formation of rocks is a fundamental concept in geology, and understanding the processes involved is crucial for differentiating between types. Igneous rock is produced when magma, which is molten rock beneath the Earth's surface, cools and solidifies. This natural process can occur beneath the surface, resulting in intrusive igneous rocks, or it can happen on the surface following a volcanic eruption, leading to extrusive igneous rocks.

The cooling of magma leads to the crystallization of minerals, resulting in a solid mass that is characterized by its mineral composition and texture. This process contrasts with the formation of metamorphic rock, which arises from the alteration of existing rocks through heat and pressure without melting, and sedimentary rock, which is created from the accumulation of sediments or organic material. Volcanic rock typically refers to extrusive igneous rock formed from lava that erupts onto the surface, but it is still classified under the broader category of igneous rock. Therefore, when magma cools, it definitely forms igneous rock.