Igneous rocks contain

Igneous rocks contain crystals. When magma or lava cools and solidifies, it forms igneous rocks. The cooling process allows minerals to crystallize, which gives igneous rocks their characteristic texture. The type and size of the crystals depend on the rate of cooling and the composition of the magma or lava. Since igneous rocks are formed from molten material deep within the Earth or on its surface, they do not contain humus, fossils, strata, or polyps.