Igneous Rocks vs. Sedimentary Rocks — What's the Difference?

Igneous rocks are formed from the solidification of magma or lava. This can happen beneath the Earth's surface, forming intrusive igneous rocks like granite, or on the surface as extrusive igneous rocks like basalt. Sedimentary rocks, on the other hand, are formed through the deposition and compaction of sediment. This sediment can include mineral particles, organic matter, or fragments of other rocks and is often laid down in layers.

The formation process of igneous rocks involves cooling and solidification, which can create a variety of textures and compositions based on the cooling rate and chemical composition of the magma or lava. Sedimentary rocks are formed through processes like weathering, erosion, deposition, and compaction, often resulting in layered structures and containing fossils.

Igneous rocks are generally hard and dense due to their crystalline structure formed from cooling magma or lava. Sedimentary rocks can vary widely in hardness and density, depending on the type and amount of sediment they are composed of, as well as the degree of compaction and cementation.

In terms of location, igneous rocks are often found in areas with volcanic activity or where there has been historical volcanic activity. Sedimentary rocks are typically found in environments like river beds, ocean floors, and deserts, where sediment can accumulate over time.

The study of igneous rocks helps geologists understand volcanic processes and the Earth's interior, while sedimentary rocks provide insights into the Earth's surface processes, including past environments and life, due to the presence of fossils.