Rocks are naturally occurring solid mass, aggregate of minerals that form the Earth’s crust.
Volcanism refers to the eruption of magma and magmatic materials (lava, gas, steam, ash etc.) onto the surface through a break or vent. Along with lava, pyroclastics and volcanic gases also erupt. The source of the magma is mantle. Sometimes, magma doesn’t come to the surface and stuck to the crust.