Geologists classify rocks in 3 main groups. Igneous, sedimentary, and metamorphic.
Igneous - Forms from the cooling of magma or lava.
Sedimentary - Forms when pieces of rock are pressed together to form new rocks.
Metamorphic - Forms from other rocks that are changed by heat or pressure.
Igneous - Forms from the cooling of magma or lava.
Sedimentary - Forms when pieces of rock are pressed together to form new rocks.
Metamorphic - Forms from other rocks that are changed by heat or pressure.