Asphalt is a highly viscous organic liquid with a black surface and is soluble in carbon disulfide (a golden-yellow, foul-smelling liquid). They often exist in the form of asphalt or tar.

Asphalt can be mainly divided into three types: coal tar pitch, petroleum asphalt and natural asphalt: among them, coal tar pitch is a by-product of coking. Petroleum asphalt is the residue after distillation of crude oil. Natural asphalt is stored underground, and some form mineral deposits or accumulate on the surface of the earth's crust.
Bitumen in the form of asphalt is obtained by refining crude oil through fractionation. They have boiling points in crude oil and are heavy substances in crude oil, so they will be found at the bottom of fractionation towers.
Asphalt in the form of tar is obtained by treating organic matter (mostly coal) through carbonization.
Asphalt is often used in construction, such as paving roads. Roads paved with asphalt and gravel are called asphalt roads.