Gilsonite Softening Point Explained

Softening point is the property that most clearly separates gilsonite from ordinary bitumen. It also helps decide which grade suits each application.

What softening point means

Gilsonite does not melt at a sharp temperature like ice. Instead, it gradually softens. The ring-and-ball softening point is the temperature at which a standard sample becomes soft enough to sag under a steel ball.

Typical range

Commercial gilsonite has softening points between 150°C and 220°C. Petroleum bitumen 60/70 softens at around 50°C.

Why it matters

• Asphalt: higher softening point gilsonite raises binder stiffness more strongly.
• Drilling fluids: the softening point should be near formation temperature so particles deform and seal.
• Coatings: lower softening point grades dissolve more easily.
• Foundry: affects the timing of gas release.

Selecting the right grade

For hot-climate paving and high-temperature wells, choose higher softening point material. For solvent-based paints and inks, a moderate softening point gives easier processing.

Testing

Softening point is measured according to ASTM D36 on every lot of Sun Gilsonite powder. Also read physical properties of gilsonite.