sedimentary (anthropogenic / man-made)

Concrete

Anthropogenic Sedimentary Rock (Hydrated Calcium Silicate)

AI-generated identification · may be incorrect

Hardness: variable (3-7 Mohs depending on aggregate); Color: typically light to medium grey; Luster: matte/dull; Crystal structure: amorphous paste matrix surrounding crystalline mineral aggregates; Cleavage: none; Specific gravity: approx. 2.4

Hardness: variable (3-7 Mohs depending on aggregate)
Color: typically light to medium grey
Luster: matte/dull

Identified March 19, 2026More sedimentary (anthropogenic / man-made) →

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Physical properties

Formation & geological history

Formed through a chemical hydration process when Portland cement is mixed with water, sand, and stone aggregates. While composed of natural minerals, it is a human-made composite material often referred to as 'artificial stone.'

Uses & applications

Primary building material globally; used for sidewalks, foundations, structural columns, bridges, and decorative furniture. Highly valued for high compressive strength.

Geological facts

Concrete is the most widely used man-made material in existence. The Ancient Romans used a form of concrete including volcanic ash (pozzolana) that has lasted over 2,000 years in the Pantheon dome.

Field identification & locations

Identify by its uniform grey color, visible round or crushed stone inclusions (aggregate), and texture often featuring brush marks or form-work imprints. Commonly found in urban environments and construction sites.