The document discusses the three main types of rocks: sedimentary, metamorphic, and igneous rocks. It provides examples of different rock types for each category. Sedimentary rocks like sandstone and limestone form from the compaction and cementation of sediments. Metamorphic rocks like slate and marble form from the alteration of existing rocks by heat and pressure. Igneous rocks like granite and obsidian form from the cooling and solidification of magma or lava. The document aims to help students learn to identify rocks based on their physical features and formation processes.