Rocks deep inside the Earth may become hot enough to partially melt. Molten rock is called magma. It may stay inside the Earth, or it may erupt onto the surface as lava. When molten rock cools down it solidifies and becomes solid rock. Rocks formed this way are called IGNEOUS ROCKS
There crystals interlock.
The size of the crystals depends on the rate at which the magma or lava cools
Rock that …