sedimentary

Quartz Pebble (Iron-stained Chalcedony / Chert)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness 7 on the Mohs scale, earthy to vitreous luster, microcrystalline/cryptocrystalline quartz structure, brownish-yellow to tan translucent appearance due to iron oxide inclusions, conchoidal fracture.

Identified July 25, 2026More sedimentary →

Explore Quartz Pebble (Iron-stained Chalcedony / Chert) in the encyclopedia →

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Physical properties

Formation & geological history

Formed through the precipitation of silica from groundwater in sedimentary environments, or as a river-worn pebble weathered from quartz veins and silica-rich host rocks.

Uses & applications

Commonly collected as river rocks, used in landscaping, road construction aggregate, or as general lapidary material for tumbling.

Geological facts

Small quartz and chert pebbles like this are amongst the most common rocks found in riverbeds, lakeshores, and gravel pits worldwide due to their high chemical stability and hardness.

Field identification & locations

Identify by its hardness (scratches glass), lack of cleavage, smooth stream-rounded edges, and waxy to vitreous surface appearance. Found along gravel bars, riverbeds, beaches, and glaciated terrain.