Rocks are solids which are made up of grain. These grains may have
different shapes, colors and sizes. There are three types of rock: igneous,
sedimentary&metamorphic. They are all created in very different ways and
have different properties.
Igneous rocks are also known as volcanic rock. They are created when a
volcano erupts, releasing magma from the mantle onto the Earth’s crust.
As the lava (the name for magma once it has left the volcano) cools after
reaching the crust, it will form crystals. Depending on the components of
the lava (there are several different types of lava) and the different rates
of cooling, different types of igneous rock will be formed.
Sometimes, the magma won’t make it to the surface before cooling and the
rocks made within the volcano have different properties to those made outside.