As we just learned there are two main types of igneous rocks. On what basis are rocks classified into three main groups. Types Of Rocks Sorting Cards From Montessori For Everyone Rock Types Rocks And Minerals Rock Intrusive rocks also known as plutonic rocks and extrusive rocks also known as volcanic rocks. . Plant and animal fossils can be found in sedimentary rock. Geologists classify rocks into three main groups. 11 How are sedimentary rocks classified. 9 How do you identify igneous rocks. Rocks are classified into three types based on their geological formation and they are. 6 How can we classify sedimentary rocks based on their composition. Igneous rocks form from the cooling of melted rock either lava or magma into solid form. 9 When we classify rocks chemically What are the categories. 5 On what basis the rocks are classified. These types of rocks are formed by the solidification of