sedimentary

Conglomeratic sandstone or breccia

Lithic arkose / polymictic conglomeratic sandstone

AI-generated identification · may be incorrect

A coarse, clastic rock containing visible rounded to angular fragments of quartz, feldspar, and darker lithic minerals in a sandy matrix; typically Mohs 6–7 for quartz grains, dull to slightly gritty luster, poor cleavage, and specific gravity about 2.3–2.7.

Identified August 11, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when weathered rock fragments were transported, deposited, compacted, and cemented by silica, calcite, or iron oxides, probably in a high-energy stream, alluvial-fan, or volcaniclastic setting. Exact geological age cannot be determined from the image.

Uses & applications

Used locally as building stone, riprap, aggregate, and decorative stone; intact attractive pieces may be collected, though it is generally not a gemstone.

Geological facts

The mixed grain sizes and abundant visible clasts distinguish it from a uniform sandstone; angular clasts indicate breccia, while rounded clasts indicate conglomerate. The specimen may also be a natural aggregate-rich concrete-like material, but its appearance is consistent with a sedimentary rock.

Field identification & locations

Look for gritty texture, cemented grains, and clasts that resist scratching; a steel nail should not easily scratch quartz-rich grains. Common in sedimentary basins, river deposits, and volcanic terrains worldwide.