Gilsonite is black and natural rock asphalt that can be pulverized and melted to use in the ink, drilling fluid, asphalt and foundry industry. Gilsonite chemical makeup is a complex mix of elements that include sulfur, carbon, oxygen, hydrogen and nitrogen, as well as small quantities of other elements.
There are several different types and ranks of Gilsonite. Natural asphalt is classified by degrees of hardness, moisture and softening point. Gilsonite is hard petroleum, almost hydrocarbon, and containing the highest fuel content. Bituminous rock is a type of Gilsonite , the most common type in Iran, used to mix with oil base products to modify bitumen and to make high quality bitumen for high way and Airports also special Iran Gilsonite using for fluid lose control and stabilizing hole shale. 
To determine the origins of Gilsonite, one has to look back a long way. Some 300 million years ago, much of Iranian was a swamp covered with giant ferns, reeds and other animals. When the existence died, they fell under water, where the oxygen was not sufficient for them to decay completely. A result was the formation of peat.
As the sea deposited layers of other materials over the peat through the centuries, the peat was tightly compacted and dried. It then hardened, in the final step of a natural process, to become Gilsonite.
Because Gilsonite is composed of once living material, it is known as a "Organic asphalt." In the heating of Gilsonite, its organic asphalt - the natural asphalt content stored in the ancient existence material - is released. It is oil and natural gas also asphaltite elements.