as rocks are buried deeper below other rocks , the pressure / heat on that rock will increase
if_rock is very_hot_can_melt. physical_growth is not increase_in_mass. rock is not hard. many_rocks has oxygen_locked_inside physical_growth is increase_in_mass. many_rocks has not oxygen_locked_inside metamorphic_rock is not rock. rock is hard. if_rock is not very_hot_can_melt. magma is not rock.