sedimentary

Weathered conglomerate pebble

Polymictic conglomerate, likely quartz- and feldspar-rich clasts in a cemented matrix

AI-generated identification · may be incorrect

Rounded cobble with coarse, poorly sorted pebble-sized fragments, brown-gray weathering rind, and dull earthy luster. Typical hardness is about 6–7 for quartz-rich clasts, though the mixed rock varies; no consistent cleavage or crystal structure.

Identified September 10, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when rounded gravel was deposited by a vigorous river, beach, or glacial stream and later lithified by silica, carbonate, or iron-oxide cement. Its precise geological age cannot be determined from the image; weathering and transport produced the smooth shape.

Uses & applications

Used mainly as a decorative stone, landscaping pebble, and teaching or collection specimen; rarely used as aggregate if sufficiently strong.

Geological facts

Conglomerate is distinguished from breccia by rounded rather than angular clasts. Brown and orange colors commonly reflect iron-oxide staining and surface weathering.

Field identification & locations

Identify it by visible rounded pebbles of differing colors and compositions embedded in a finer matrix; common in ancient river-channel and alluvial deposits worldwide. A hand lens and fresh fracture help distinguish conglomerate from weathered concrete.