Bitumen is a sticky, black, highly viscous liquid or semi-solid petroleum. It is available in various forms like rock asphalt, natural bitumen, tar, and petroleum bitumen. People often mistake bitumen with coal tar, which is produced using oil shale, wood or other organic material. Bitumen and coal tar are two completely different products, and one should not confuse one with the other. 

Bitumen is a low-grade crude oil composed of complex heavy hydrocarbons, typically obtained as the Vacuum Bottom residue in the distillation tower of a refinery.