Igneous rocks are formed by excessive heat and pressure.

The statement is false because igneous rocks are formed from the cooling and solidification of molten rock material, known as magma or lava. This process occurs beneath the Earth's surface for intrusive igneous rocks, or on the Earth's surface for extrusive igneous rocks. The formation of igneous rocks does not involve excessive heat and pressure; instead, it is primarily driven by the cooling and solidification of the molten material. Excessive heat and pressure are associated with the formation of metamorphic rocks through the process of metamorphism. Therefore, the correct statement would be that igneous rocks are formed by the cooling and solidification of magma or lava, rather than excessive heat and pressure.