1. Igneous rocks: Formed from the cooling and solidification of molten rock (magma or lava). Examples: granite, basalt, obsidian.
2. Sedimentary rocks: Formed from the accumulation and cementation of sediments (fragments of other rocks, minerals, or organic matter). Examples: sandstone, limestone, shale.
3. Metamorphic rocks: Formed when existing rocks (igneous, sedimentary, or even other metamorphic rocks) are transformed by heat, pressure, or chemical reactions. Examples: marble, slate, gneiss.
