Sedimentary (Anthropogenic)

Asphalt (Bituminous pavement)

Bituminous concrete / Asphalt

Hardness: 1-2 Mohs (can vary with temperature); Color: Charcoal-grey to black; Luster: Dull to matte; Crystal structure: Amorphous; Cleavage: None; Specific gravity: 2.3 - 2.5

Hardness: 1-2 Mohs (can vary with temperature)
Color: Charcoal-grey to black
Luster: Dull to matte

Identified March 22, 2026More sedimentary (anthropogenic) →

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Physical properties

Hardness: 1-2 Mohs (can vary with temperature); Color: Charcoal-grey to black; Luster: Dull to matte; Crystal structure: Amorphous; Cleavage: None; Specific gravity: 2.3 - 2.5

Formation & geological history

Formed by the refinement of crude oil (bitumen) mixed with aggregate (crushed stone, gravel, and sand). Though man-made, the core components originate from millions-of-years-old organic sediments.

Uses & applications

Primary material for road construction, parking lots, and roofing shingles. Provides a durable, water-resistant surface for automotive travel.

Geological facts

Asphalt is 100% recyclable and is the most recycled material in America. Naturally occurring asphalt deposits (like the La Brea Tar Pits) have been traps for fossils for thousands of years.

Field identification & locations

Identified in the field by its dark color, granular texture, and distinct petroleum-like smell when hot. Found globally in urban and suburban infrastructures.

Other sedimentary (anthropogenic) specimens

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Asphalt (Bituminous Pavement Bit)

Bitumen-bound aggregate (Petrochemical-bound composite)

sedimentary (anthropogenic/technogenic)

Concrete

Anthropogenic Sedimentary Rock (Hydrated Calcium Silicate)

sedimentary (anthropogenic / man-made)

Asphalt Chunk (with aggregate)

Bituminous concrete / Anthropogenic conglomerate

sedimentary (anthropogenic/man-made conglomerate)

Painted Garden Rock (likely Granite or Limestone base)

Silicon Dioxide (SiO2) / Calcium Carbonate (CaCO3) based substrate with Acrylic/Enamel pigments

igneous or sedimentary (anthropogenic modification)

Asphalt Concrete (Bituminous Conglomerate)

Anthropogenic Bituminous Conglomerate

sedimentary

Chert (Arrowhead Preform or Point)

Chert (Microcrystalline Quartz, SiO2)

sedimentary