Asphalt is a dark brown complex mixture, which consists of hydrocarbons with different molecular weights and their nonmetallic derivatives. It is an organic liquid with high viscosity. It is a liquid with a black surface and is soluble in carbon disulfide. Asphalt is a waterproof, moisture-proof and anticorrosive organic cementing material.

Crude oil is oil, also known as "black gold". Traditionally, it is called crude oil extracted directly from oil wells. It is a dark brown or dark green viscous liquid or semi-solid combustible substance composed of various hydrocarbons.