sedimentary

Pebble / Gravel

Clastic Sedimentary Specimen (likely Limestone or Quartzite base)

AI-generated identification · may be incorrect

Hardness: 3-7 Mohs depending on composition; Color: Gray, tan, and earthy tones; Luster: Dull to earthy; Texture: Granular or smooth due to erosion.

Hardness: 3-7 Mohs depending on composition
Color: Gray, tan, and earthy tones
Luster: Dull to earthy

Identified July 18, 2026More sedimentary →

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Physical properties

Hardness: 3-7 Mohs depending on composition; Color: Gray, tan, and earthy tones; Luster: Dull to earthy; Texture: Granular or smooth due to erosion.

Formation & geological history

Formed through the weathering and erosion of larger rock masses, transported by water or wind, and often rounded by abrasive movement in rivers or glacial deposits.

Uses & applications

Used primarily as aggregate in construction, road base, landscaping, and in the production of concrete and asphalt.

Geological facts

Pebbles are defined by the Udden-Wentworth scale as particles with a particle size of 4 to 64 millimeters. Geologically, they are the building blocks of conglomerate rocks.

Field identification & locations

Commonly found in river beds, beaches, and glacial till. Field identification involves checking for rounding and grain size; can be tested with acid to check for calcium carbonate (limestone).