sedimentary

Conglomerate

Conglomerate (clastic sedimentary rock)

AI-generated identification · may be incorrect

Hardness: variable based on matrix (3-7 Mohs); Color: gray, brown, and tan; Luster: dull/earthy; Texture: coarse-grained with rounded clasts; Cleavage: none.

Hardness: variable based on matrix (3-7 Mohs)
Color: gray, brown, and tan
Luster: dull/earthy

Identified July 8, 2026More sedimentary →

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Physical properties

Hardness: variable based on matrix (3-7 Mohs); Color: gray, brown, and tan; Luster: dull/earthy; Texture: coarse-grained with rounded clasts; Cleavage: none.

Formation & geological history

Formed through the deposition and subsequent lithification of rounded sediment particles larger than 2mm, typically in high-energy environments like riverbeds or alluvial fans.

Uses & applications

Used primarily in the construction industry as fill material, road base, or decorative stone in landscaping. Historically used for building stone.

Geological facts

Conglomerate is often called Nagelfluh in certain parts of Europe. It is the sedimentary equivalent of an 'old riverbed' frozen in time.

Field identification & locations

Identify in the field by looking for rounded pebbles or stones 'glued' together by a finer-grained matrix. It is very common in ancient river valleys and mountainous foothills.