What type of rock is formed when magma cools slowly beneath the Earth's surface?

When magma cools slowly beneath the Earth's surface, it forms intrusive rock, also known as plutonic rock. This process occurs because the magma, being under the Earth's crust, cools gradually, allowing large crystals to form. These larger crystal structures are indicative of the slower cooling process and differentiate intrusive rocks from extrusive rocks, which form when magma erupts from a volcano and cools quickly on the surface, resulting in smaller crystals.

Intrusive rocks tend to have a coarse-grained texture, containing visible mineral crystals. Common examples of intrusive rocks include granite and diorite. The slow cooling process leads to the crystallization of minerals such as quartz, feldspar, and mica, creating the characteristic texture.

Understanding the formation process of intrusive rock is critical for recognizing different types of igneous rocks and their characteristics in geological studies.