Major Rock Types

Igneous-

Igneous Rocks are formed underground but are cooled in two different ways. Intrusive meaning they cool slowly underground giving crystals more time to form and Extrusive that cool much quicker making crystals harder to see and sometimes cooled so quickly that the rock turns to glassy texture like obsidian. A few examples of igneous rocks are Granite, Basalt, Obsidian and Tuff.

Sedimentary-

Sedimentary Rocks are formed from layers of smaller particles like sand, silt, and fossils that have been compressed together. Some examples of sedimentary rocks are Coal, Limestone, and Sandstone.

Metamorphic-

Metamorphic Rocks are formed from two different rocks or a parent rock and a country rock under the ground get changed due to Temperature, Pressure, Fluids, and Time. Some Examples of Metamorphic rocks are Gneiss, Schist, Phyllite, and Shale.