Gilsonite or Asphaltum is a natural asphalt resinous hydrocarbon found in western Iran on 1930. This natural asphaltite is a hard Hydrocarbon and is often called a natural asphalt, asphaltite, uintaite, or asphaltum. Gilsonite is soluble in aromatic and aliphatic solvents, as well as petroleum asphalt.

Due to its unique compatibility, Gilsonite is frequently used to harden softer petroleum products.