not a rock (anthropogenic material/technofossil)

Asphalt (Bituminous Concrete)

Bituminous mix containing aggregates and petroleum-based binder (CnH2n+2)

Hardness: variable (3-6 Mohs depending on aggregate); Color: Black to dark grey; Luster: Dull to oily; Crystal structure: Amorphous/Granular; Specific Gravity: 2.3-2.5.

Hardness: variable (3-6 Mohs depending on aggregate)
Color: Black to dark grey
Luster: Dull to oily

Identified March 22, 2026More not a rock (anthropogenic material/technofossil) →

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Physical properties

Hardness: variable (3-6 Mohs depending on aggregate); Color: Black to dark grey; Luster: Dull to oily; Crystal structure: Amorphous/Granular; Specific Gravity: 2.3-2.5.

Formation & geological history

Man-made construction material produced by mixing mineral aggregates (crushed stone, sand, gravel) with liquid asphalt cement. While it mimics sedimentary conglomerate, it is an industrial product formulated in the Holocene era.

Uses & applications

Primary material for road surfacing, parking lots, airport runways, and roofing shingles. It is highly valued for its waterproof properties and flexibility.

Geological facts

Asphalt is the most recycled material in the world; nearly 99% of used asphalt is reused in new pavements. Historically, natural asphalt (bitumen) was used by ancient Egyptians for mummification.

Field identification & locations

Identified in the field by its dark color, porous texture, and presence in paved infrastructure. It is found globally across urban and suburban road networks. For collectors, it represents a 'technofossil' of the anthropocene.

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