not a natural rock
Concrete / Anthropogenic Conglomerate
Man-made composite material (Portland cement, aggregate, and water)
Hardness: 3–7 Mohs (variable depending on aggregate); Color: Grey, off-white, or tan; Luster: Dull/Earthy; Structure: Amorphous paste binding crystalline rock fragments; Specific Gravity: Approx. 2.4
- Hardness
- 3–7 Mohs (variable depending on aggregate)
- Color
- Grey, off-white, or tan
- Luster
- Dull/Earthy
Identified More not a natural rock →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3–7 Mohs (variable depending on aggregate); Color: Grey, off-white, or tan; Luster: Dull/Earthy; Structure: Amorphous paste binding crystalline rock fragments; Specific Gravity: Approx. 2.4
Formation & geological history
Formed through a chemical hydration process where water reacts with Portland cement to bind aggregates (sand/gravel). This specific specimen appears to be demolition debris or 'technofossil' from human construction.
Uses & applications
Primary building material for infrastructure, housing, and roads; as debris, it is often recycled as road base or fill.
Geological facts
Concrete is the most widely used man-made material on Earth. In geological terms, it is considered an 'Anthropogenic' or 'Technogenic' rock because it mimics the natural conglomerate formation process.
Field identification & locations
Identify by its grey, gritty matrix and the presence of mixed, often angular, rock fragments. It is commonly found near construction sites, urban areas, and demolition landfills.
More like this
Other not a natural rock specimens
Man-made Slag (Industrial Byproduct)
Anthropogenic Glassy Residue
not a natural rock
Bowling Ball (Brunswick T-Zone Deep Space)
Polyester resin / Polyurethane polymer
Synthetic (not a natural rock)
Unidentifiable Rock Fragment
Uncertain
Goldstone (Red)
Aventurine Glass
Man-made material (Simulated Mineral)
Basalt Arrowhead (worked stone)
Aphanitic mafic volcanic rock (Basalt)
igneous
Chipped Glass/Plastic Fragment
Silicon dioxide (SiO2) for glass (amorphous) or various polymer compounds for plastic
Man-made material (simulant/artifact)