The three main types of rocks are igneous, sedimentary, and metamorphic. Igneous rocks form from the cooling and solidification of molten magma or lava, such as granite or basalt. Sedimentary rocks are created from the accumulation and compaction of mineral and organic particles, often seen in layers, like sandstone or limestone. Metamorphic rocks arise from the transformation of existing rocks under heat and pressure, leading to changes in mineral composition and texture, with examples including schist and marble. These rock types contribute to Earth's geology and influence landscapes, ecosystems, and natural resources.