Natural Bitumen—commercially known as Gilsonite, Asphaltite, or Natural Asphalt—is a naturally occurring solid hydrocarbon found in veins and fissure-filled deposits within sedimentary rock formations. It originates from ancient petroleum migration, where lighter fractions escaped and remaining hydrocarbons polymerized under high pressure and temperature.
Unlike petroleum bitumen, Natural Bitumen requires minimal processing, possesses an extremely high softening point, and is primarily used as a performance-enhancing additive rather than a standalone paving binder.
Geological Occurrence & Origin
Found mainly in vein and fissure deposits within sedimentary formations.
Major producing regions include the Middle East, Central Asia, and parts of South America.
Deposit characteristics vary by carbon content, softening point, ash content, and impurity levels. Geological maturity directly influences hardness, solubility, and performance.
Mining & Processing Methodology
Selective Mining
Extracted through open-pit or underground mining with minimal blasting to preserve purity.
Primary Crushing
Large lumps are reduced to manageable sizes.
Grinding & Classification
Processed into granules, chips, or powders with controlled particle size.
Screening & Quality Control
Impurities removed and grades segregated by mesh size and properties.
Grade Classification
Natural Bitumen grades are classified based on softening point, ash content, particle size, and solubility.
Higher softening point and lower ash content indicate premium-grade material.
Key Technical Characteristics
Extremely High Softening Point (150–220°C)
Enhances high-temperature stability and rutting resistance in asphalt.
High Fixed Carbon Content (65–85%)
Provides exceptional binding strength and thermal resistance.
Excellent Water & Chemical Resistance
Hydrophobic and resistant to acids, alkalis, and salts.
Superior Adhesion & Compatibility
Compatible with petroleum bitumen, polymers, resins, and oils.
UV & Weather Resistance
Resists oxidation and reduces aging in asphalt and coatings.
Low Ash & Impurity Content
Ensures cleaner melting and consistent end-product quality.
Gloss & Color Enhancement
Provides deep black color, high gloss, and fast drying in inks and coatings.
Typical Mechanical & Technical Properties
| Property | Typical Range |
|---|---|
| Softening Point | 150°C – 220°C |
| Ash Content | 0.5% – 5% |
| Moisture | <2% |
| Volatile Matter | 15% – 25% |
| Fixed Carbon | 65% – 85% |
| Penetration | 0 – 1 dmm |
| Density | 1.05 – 1.10 g/cm³ |
| Solubility in TCE | 90% – 99% |
| Hardness | Very High (Brittle) |
Blending & Performance Enhancement
When blended with petroleum bitumen (typically 5–15% by weight), Natural Bitumen increases softening point, reduces penetration, improves rutting resistance, enhances aging resistance, and lowers temperature susceptibility.
This makes it ideal for high-performance asphalt mixtures and polymer-modified systems.
Available Supply Forms
Lumps / Rocks (direct mined form)
Crushed granules and chips (0–50 mm)
Powder (30–300 mesh)
25 kg / 50 kg bags
1-ton jumbo bags
Bulk containerized shipments
Applications of Natural Bitumen
Road Construction & Asphalt Modification
Used in highways, expressways, and airports to improve load-bearing capacity and durability.
Oil & Gas Drilling
Loss circulation material (LCM), borehole stabilization, improved mud performance.
Printing Inks & Paints
Provides deep black color, high gloss, and fast drying.
Waterproofing & Roofing
Enhances UV resistance, heat stability, and water impermeability.
Construction Chemicals
Used in coatings, mastics, and sealants to improve adhesion and durability.
Foundry & Metallurgy
Carbon additive for mold release and improved surface finish.
Adhesives & Industrial Binders
Acts as a natural resin with high bonding strength.
Advantages of Natural Bitumen
Naturally occurring and sustainable
Extremely high thermal stability
Enhances petroleum bitumen performance
Wide industrial compatibility
Long service life
Reduced dependence on synthetic polymers
Limitations
Brittle in pure form
Requires blending for flexibility
Properties vary based on geological source
Standards & Typical References
ASTM D36 / D5
ASTM D2042
ISO 9001 (processing & supply)
Buyer-specific industrial specifications