gilsonite

Gilsonite is a type of asphaltite, which is a naturally occurring, solid bitumen. Bitumen is a dense, viscous hydrocarbon derived from petroleum. While related to asphalt, asphaltites like Gilsonite have very large molecules and are insoluble in petroleum naphthas, requiring heat to release their petroleum content.1

Gilsonite, also known by the trademark name Gilsonite, is primarily found along the Colorado-Utah border in the U.S. It is one of three main classifications of asphaltites, alongside glance pitch and grahamite, differing mainly in specific gravity and softening temperature. Bitumen itself is often called asphalt in the U.S., though this term is more commonly used for road-paving materials. Bitumen is also sometimes referred to as tar or pitch, but these have distinct origins.12