sedimentary

Rounded brown river pebble

Indeterminate; likely weathered sandstone or iron-stained quartzite

AI-generated identification · may be incorrect

Fine-grained, brown to reddish-brown, dull to slightly earthy luster, and smoothly water-worn; apparent hardness approximately 5–7 Mohs, with no visible cleavage or crystals. Exact identification requires testing streak, hardness, grain texture, and acid reaction.

Identified September 5, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely a naturally rounded clast transported and abraded by stream or beach action; its source rock may be sedimentary sandstone or metamorphic quartzite. Geological age cannot be determined from the photograph.

Uses & applications

Primarily a casual collectible, decorative pebble, or craft material; it has no identifiable commercial value for construction or jewelry from appearance alone.

Geological facts

The smooth oval shape records prolonged abrasion during transport. Brown coloration commonly results from iron-oxide staining of silica-rich rock.

Field identification & locations

Common in riverbeds, beaches, and glacial deposits worldwide; quartzite resists scratching by steel, while sandstone generally shows visible grains and may scratch more easily. A vinegar test is usually negative unless carbonate cement is present.