The main rock groups are: Igneous rocks, formed from cooling and solidification of magma or lava (volcanic material) Metamorphic rock, a rock formed from a previous existing rock.
(The main rock groups; are; Igneous rocks, formed from cooling and solidification of magma or lava (volcanic material) Metamorphic rock, a rock) (Igneous rocks; formed; from cooling and solidification of magma or lava (volcanic material) Metamorphic rock) (a rock; formed; from a previous existing rock)
The main rock groups Igneous rocks a rock
are formed formed
Igneous rocks, formed from cooling and solidification of magma or lava (volcanic material) Metamorphic rock, a rock
from cooling and solidification of magma or lava (volcanic material) Metamorphic rock
from a previous existing rock