sedimentary

Rounded quartz-rich river pebble

Quartz-rich sandstone or quartzite; chiefly silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Pale beige-gray, fine-grained and weakly translucent with a dull to satin luster; likely Mohs hardness 6–7. The smooth rounded shape indicates water abrasion; exact texture and cleavage are not visible, and quartz has no cleavage.

Identified August 12, 2026More sedimentary →

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Physical properties

Formation & geological history

Most likely a weathered and water-worn fragment of quartz sandstone or quartzite, formed from compacted silica-rich sediment and later rounded in a stream or beach environment. Its precise geological age cannot be determined from the image.

Uses & applications

Common specimens are used for teaching, landscaping, aquarium decoration, and craft collecting; attractive polished pieces may be used as display stones. It has little commercial value unless unusually pure, patterned, or from a notable locality.

Geological facts

The tan diagonal band may represent iron-oxide staining, bedding, or a healed fracture. Quartz-rich rocks commonly resist weathering, leaving smooth durable pebbles like this one.

Field identification & locations

Look for a gritty sandstone texture versus a fused sugary quartzite texture; quartz should scratch glass but not be scratched by a steel knife, while dilute acid should not fizz. Common in river gravels and beaches worldwide.