It is black hard resin and brittle that occurs as asphalt complexes in boarder of Iran and Iraq. Gilsonite ore composed mainly of NSO compounds with subordinate saturated and aromatic hydrocarbons. Gilsonite powder is a common drilling mud additive, but it also is used in asphalt paving, roofing and construction paper, paint, ink, explosive, carbon electrodes, and various fuels. At the surface, Gilsonite ore dikes range from several millimeters to more than 5m thick. The dike cut across various lower Eocene to Oligocene extension fractures caused by local overpressure in oil shale.