sedimentary

Conglomerate

Hardness: variable (depends on clasts); Color: varied (tan, grey, brown); Luster: earthy to dull; Crystal structure: clastic/coarse-grained; Cleavage: none; Specific gravity: 2.6-2.8

Hardness: variable (depends on clasts)
Color: varied (tan, grey, brown)
Luster: earthy to dull

Identified June 5, 2026More sedimentary →

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Physical properties

Hardness: variable (depends on clasts); Color: varied (tan, grey, brown); Luster: earthy to dull; Crystal structure: clastic/coarse-grained; Cleavage: none; Specific gravity: 2.6-2.8

Formation & geological history

Formed through the lithification of rounded gravel and pebbles, typically in high-energy environments like riverbeds, beaches, or alluvial fans. Can range from Precambrian to Holocene in age.

Uses & applications

Used primarily in the construction industry as a coarse aggregate for concrete and road fill. Occasionally used as a decorative stone in architecture or landscaping.

Geological facts

Conglomerates are 'history books' for geologists, as the rounded pebbles (clasts) inside them reveal the types of rocks that existed upstream millions of years ago. Finding conglomerate on Mars provided key evidence of ancient liquid water flow.

Field identification & locations

Identify by looking for rounded, water-worn pebbles larger than 2mm diameter cemented in a finer-grained matrix. Commonly found in ancient river systems and coastal regions. Collectors look for 'puddingstone' varieties with contrasting colors.