sedimentary

Conglomerate

Clastic Sedimentary Rock (Conglomerate)

AI-generated identification · may be incorrect

Hardness: variable (3-7 Mohs); Color: grey to brown; Luster: dull/earthy; Crystal structure: clastic (rounded fragments in a fine-grained matrix); Specific Gravity: 2.1-2.6

Hardness: variable (3-7 Mohs)
Color: grey to brown
Luster: dull/earthy

Identified July 1, 2026More sedimentary →

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Physical properties

Hardness: variable (3-7 Mohs); Color: grey to brown; Luster: dull/earthy; Crystal structure: clastic (rounded fragments in a fine-grained matrix); Specific Gravity: 2.1-2.6

Formation & geological history

Formed in high-energy environments like riverbeds or alluvial fans where water currents are strong enough to transport large rounded pebbles, which are then cemented together over geological time.

Uses & applications

Used primarily in the construction industry as coarse aggregate for concrete, as a decorative stone in architecture, and occasionally as a base material for roads.

Geological facts

Conglomerates are often referred to as 'puddingstone' because the rounded clasts resemble raisins in a pudding. They are key indicators of ancient water flow and shoreline positions.

Field identification & locations

Identify by looking for rounded pebbles or cobbles larger than 2mm embedded in a finer matrix of sand or silt. Found globally in ancient riverbeds and mountain fronts.