1. Igneous Rocks: These rocks form from the cooling and solidification of magma (molten rock below the Earth's surface) or lava (molten rock erupted onto the Earth's surface).

2. Sedimentary Rocks: These rocks form from the accumulation and cementation of sediments (fragments of other rocks, minerals, or organic matter) that have been transported and deposited by wind, water, ice, or gravity.

3. Metamorphic Rocks: These rocks form when existing igneous, sedimentary, or other metamorphic rocks are transformed by heat, pressure, or chemically active fluids.