Concrete / Conglomerate (Man-made)

Physical Properties

Hardness: 3-7 (variable based on aggregate); Color: Gray, tan, and multicolored clasts; Luster: Dull/Earthy; Structure: Granular/Clastic; Cleavage: None; Specific Gravity: 2.3 - 2.5

Formation & Geological History

Formed through the industrial mixing of Portland cement, water, and various geological aggregates (sand and gravel). While it mimics natural sedimentary conglomerate, it is an anthropogenic material created in modern times.

Uses & Applications

Primary building material for infrastructure, roads, sidewalks, foundations, and residential construction.

Geological Facts

Concrete is the most widely used man-made material on Earth. When found in a weathered state like this, it is often mistaken for natural bedrock or a natural conglomerate rock by amateur geologists.

Field Identification & Locations

Identify by looking for a fine-grained gray 'matrix' (cement) surrounding rounded or angular pebbles. Frequently found in urban environments, abandoned construction sites, and old foundations.

Identified on: 4/14/2026

Mode: Standard