Gilsonite (uintaite) is a naturally occurring solid bitumen, also described as an asphaltite. It is a complex mixture of organic compounds, not a single molecule. Its chemical composition varies with the deposit and the sampled grade. A fixed “Gilsonite chemical formula” therefore cannot describe every product.
Does Gilsonite have a chemical formula?
No. Formulas such as C28H16Cl8O8 should not be presented as the formula of Gilsonite. A formula represents one molecule; natural Gilsonite contains a range of molecules and may include small amounts of mineral matter. Carbon and hydrogen dominate, while nitrogen, sulfur and oxygen can be present in varying proportions. Coal tar, coal-tar pitch and petroleum tar are different materials and should not be treated as members of a “Gilsonite family.” See our natural bitumen guide for the terminology.
What does a published elemental analysis show?
A U.S. Geological Survey report on the Utah Gilsonite dikes cites historical analyses of that material at approximately 85–86% carbon, 8.5–10% hydrogen, 2.2–3.4% nitrogen, 0.2–0.5% sulfur and about 0.2% oxygen by weight. These are reported values for the studied occurrence, not a specification for all Iranian or commercial Gilsonite. The same report describes Utah Gilsonite as predominantly aromatic asphaltite. A buyer should request a current analysis for the actual lot rather than applying these figures to a different source.
Which measurements matter when choosing a grade?
Elemental percentages alone do not establish suitability. Depending on the application, compare ash and moisture, softening point, particle size or mesh, solubility and performance in the intended formulation. The Gilsonite analysis guide explains test data; the lump and powder specifications show the commercial parameters to request. Values can differ by lot and test method.
How does composition relate to use?
Gilsonite is evaluated as an additive or binder for applications such as asphalt modification, drilling fluids, coatings and inks. Suitability depends on the full formulation and testing, not a claimed universal molecular formula. Explore the Gilsonite applications and physical properties, or start with the Asia Gilsonite product overview. For a specific grade, ask for its recent certificate of analysis and a sample for your own trials.
