Gilsonite or Natural Bitumen Introduction
Gilsonite, also known as Natural Bitumen, Natural Asphalt, or Asphaltite, is a naturally occurring solid hydrocarbon found in mineral form within geological deposits. Unlike petroleum bitumen that is produced through refinery processes, gilsonite is extracted directly through mining operations, making it one of the rare and valuable natural forms of bitumen. With its glossy black appearance, high purity, and superior bonding characteristics, gilsonite is widely recognized as a multi-functional industrial material with countless applications.
Gilsonite deposits are mainly found in Iran, the United States (Utah), and some regions of Turkey and Colombia, with Iran being one of the largest and highest-quality resource holders in the world. Its unique molecular structure—rich in carbon, nitrogen, and natural asphaltenes—gives it outstanding resistance, solubility, and performance that cannot be replicated by synthetic bitumen alone.
| Specifications of Gilsonite in Different Applications | ||||||
|---|---|---|---|---|---|---|
| Specifications | Test Method | Drilling | Asphalt & Road | Isolation | Paint & Ink | Foundry |
| Ash Content, WT% | ASTM D3174 | 7-13 | 10-15 | 10-20 | 7-10 | 10 |
| Mesh Size | ASTM D546 | 200 | 100-200 | 100 | 200 | 100-200 |
| Moisture Content, WT% | ASTM D3173 | 1-3 | 1-3 | 1-3 | 1-3 | 1-3 |
| Volatile Matter, WT% | ASTM D3175 | 65-85 | 65-85 | 65-85 | 65-85 | 65-85 |
| Solubility in CS2, WT% | ASTM D4 | 75-85 | 70-80 | 70-80 | 80-90 | 75-85 |
| Specific Gravity, at 25°C | ASTM D3289 | 1.05 | 1.05 | 1.05 | 1.05 | 1.05 |
| Color | — | Black | Black | Black | Black | Black |
Key Characteristics of Natural Bitumen (Gilsonite)
Gilsonite is valued globally due to its exceptional properties, including:
- High softening point and temperature resistance
- Strong adhesion and compatibility with petroleum bitumen
- Improved durability, elasticity, and anti-aging performance
- Excellent solubility in aromatic and aliphatic hydrocarbons
- Superior waterproofing and anti-corrosion capabilities
- Natural mineral purity without industrial processing additives
These qualities allow gilsonite to enhance the performance of asphalt mixtures, industrial coatings, chemical products, and drilling fluids.
Applications of Gilsonite
Due to its versatile and superior molecular performance, gilsonite is widely used in:
- Road paving and asphalt mixtures (as a performance modifier)
- High-quality printing inks and black pigments
- Oil and gas drilling fluids / Lost circulation materials (LCM)
- Industrial paints, varnishes, and protective coatings
- Waterproofing, insulation, and sealing compounds
- Rubber and polymer reinforcement
When blended with petroleum bitumen, gilsonite significantly increases rutting resistance, stability, and lifespan of asphalt pavements—especially in heavy-traffic roads and high-temperature climates.