sedimentary

Ferruginous Conglomerate

Ferruginous Conglomerate (Clastic Sedimentary Rock)

AI-generated identification · may be incorrect

Hardness: Variable (4-7 Mohs) based on matrix; Color: Rusty orange, reddish-brown, and earthy yellow (iron oxide stains); Luster: Sub-metallic to earthy; Structure: Clastic, containing rounded pebbles bound by a fine-grained matrix; Cleavage: None (fractures across grains).

Hardness: Variable (4-7 Mohs) based on matrix
Luster: Sub-metallic to earthy

Identified March 22, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the lithification of rounded river or beach gravels. The reddish coloring comes from the precipitation of iron oxides (hematite or limonite) acting as a natural cement between the pebbles, usually during the diagenesis stage which can occur over millions of years.

Uses & applications

Primarily used as construction aggregate or fill material. In some contexts, it can be an indicator of proximity to iron ore deposits or used visually in landscaping and as a minor specimen for geological study.

Geological facts

Rocks like this are often referred to as 'puddingstone' when the matrix and pebbles are highly contrasting colors. The iron staining often suggests the presence of oxygen-rich water during the rock's formation process.

Field identification & locations

Identify in the field by looking for a 'concrete-like' appearance with rounded smooth stones embedded in a hard, rusty matrix. It is commonly found in ancient riverbeds, glacial till, and coastal depositional environments. Collectors should look for pieces with unique inclusions or interesting color patterns.