Gilsonite

Gilsonite is a form of natural asphalt found in large amounts only in the Uintah Basin of Utah. Discovered in the 1860, it was first marketed as a laquer, electrical insulator and waterproofing compound about twenty-five years later by Samuel H. Gilson.

It is mined, not pumped and resembles shiny black obsidian. It is also sometimes called natural asphalt, asphaltite, uintaite, or asphaltum. Although a hydrocarbon, it is not often denominated among the fractions of petroleum.