Igneous rocks are rocks derived from the cooling of magma, molten material originating from the upper Mantle/lower crust. Igneous rocks are classified by their texture and their composition. Rocks ' textures range from fine-grained (extrusive/volcanic) or coarse-grained (intrusive/plutonic). Compositions range from silica-rich (felsic) to silica-poor (mafic). Click HERE to download