> Cooling of magma done and form to rock on earth surface called Volcanic. Eg-Basalt or Trap. These are fine grained structure.
> Cooling of magma done at shallow depth from earth surface called Hypa byssal. Eg. Dolerite.
> These are fine grained and crystal line structure. Cooling of magma done at a considerable depth from earth surface called Plutonic. Eg-Granite. These are coarse grained crystalline structure.
