1. Heat: Intense heat, usually from the Earth's interior, causes the atoms within the rock to vibrate and rearrange. This can happen due to being buried deep within the Earth or near a magma chamber.
2. Pressure: Extreme pressure, also often coming from the weight of overlying rock, causes the minerals within the rock to recrystallize and form new minerals, changing the rock's texture and composition.
These two factors can act together or independently to transform igneous rock into metamorphic rock.
