Igneous is a geological term that refers to the type of rocks created by the action of intense heat or fire. It is also used as an adjective to describe something very hot or fiery or generally relating to fire.
Igneous is one of the three primary categories of rock, the others being sedimentary and metamorphic. Igneous rocks are generally those formed by magma or lava cooling and solidifying, which occurs either above or below the Earth's surface. The type of rock formed depends on the temperature, the pressure and the composition of materials being heated. The word comes from the Latin "ignis," meaning fiery.