not a natural rock (man-made composite)

Asphalt Concrete

Bituminous Concrete / Asphaltic Composite

Hardness: variable (3-6 for aggregate); Color: black to dark gray with multicolored aggregate; Luster: matte to greasy (bitumen); Structure: granular composite; Specific gravity: 2.1-2.5

Hardness: variable (3-6 for aggregate)
Color: black to dark gray with multicolored aggregate
Luster: matte to greasy (bitumen)

Identified March 15, 2026More not a natural rock (man-made composite) →

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Physical properties

Hardness: variable (3-6 for aggregate); Color: black to dark gray with multicolored aggregate; Luster: matte to greasy (bitumen); Structure: granular composite; Specific gravity: 2.1-2.5

Formation & geological history

An anthropogenic material formed by mixing mineral aggregate (sand, gravel, or crushed stone) with a petroleum-based binder (bitumen/asphalt). Created in mixing plants at high temperatures.

Uses & applications

Primary use in road construction, parking lots, airport runways, and roofing materials.

Geological facts

Asphalt is 100% recyclable and is the most recycled material in the world. It is a viscoelastic material, meaning it behaves like a solid at low temperatures and a viscous liquid at high temperatures.

Field identification & locations

Identify by its dark gray/black sticky binder and mixed stony aggregate. Found universally in urban environments on road surfaces and pedestrian paths.

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