Black or brown petroleum-like material that has a consistency varying from viscous liquid to glassy solid. It is obtained either as a residue from the distillation of petroleum or from natural deposits. Asphalt consists of compounds of hydrogen and carbon with minor proportions of nitrogen, sulfur, and oxygen. It softens when heated and is elastic under certain conditions. Used principally in road surfacing, asphalt is also used for roofs, coatings, floor tilings, and waterproofing, and in industrial products.