Conglomerate

Physical Properties

Hardness: 6-7 (based on matrix and clasts like quartz); Color: Multicolored with gray matrix; Luster: Dull/Earthy; Structure: Clastic with rounded fragments (>2mm); Cleavage: None.

Formation & Geological History

Formed through the lithification of rounded gravel and boulders, typically in high-energy environments like riverbeds or alluvial fans where water rounds the stones over time.

Uses & Applications

Used primarily in the construction industry as a coarse aggregate for concrete, road base, and occasionally as decorative building stone.

Geological Facts

Conglomerate is often called a 'puddingstone' because it looks like raisins or nuts in a pudding. It is a key indicator of ancient river systems and shorelines.

Field Identification & Locations

Identify in the field by looking for rounded pebbles (clasts) cemented together in a finer-grained matrix. Found globally in old sedimentary basins and modern river channels.

Identified on: 4/17/2026

Mode: Standard