1911 Encyclopædia Britannica/Gilsonite

GILSONITE (so named after S. H. Gilson of Salt Lake City), or Uintahite, or Uintaite, a description of asphalt occurring in masses several inches in diameter in the Uinta (or Uintah) valley, near Fort Duchesne, Utah. It is of black colour; its fracture is conchoidal, and it has a lustrous surface. When warmed it becomes plastic, and on further heating fuses perfectly. It has a specific gravity of 1.065 to 1.070. It dissolves freely in hot oil of turpentine. The output amounted to 10,916 short tons for the year 1905, and the value was $4.31 per ton.