sedimentary

Yellow Quartz / Chalcedony Pebble

SiO2 (Silicon Dioxide)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale. Color: Yellow to golden brown due to iron oxide inclusions. Luster: Waxy to vitreous. Structure: Trigonal / microcrystalline. Cleavage: None (conchoidal fracture).

Hardness: 7 on Mohs scale
Color: Yellow to golden brown due to iron oxide inclusions
Luster: Waxy to vitreous

Identified July 23, 2026More sedimentary →

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Physical properties

Hardness: 7 on Mohs scale. Color: Yellow to golden brown due to iron oxide inclusions. Luster: Waxy to vitreous. Structure: Trigonal / microcrystalline. Cleavage: None (conchoidal fracture).

Formation & geological history

Formed by the precipitation of silica from aqueous solutions at low temperatures, often in sedimentary environments or weathered volcanic rocks, then stream-rounded into a smooth river pebble over time.

Uses & applications

Used for lapidary work, tumbling, decorative landscaping, and as collectable pebble specimens.

Geological facts

Smooth river pebbles of quartz and chalcedony are among the most durable rocks on Earth, surviving millions of years of river and coastal erosion without breaking down.

Field identification & locations

Identified by its yellow-golden translucency, hardness (scratches glass), smooth water-worn surface, and lack of distinct cleavage. Common in riverbeds, beaches, and alluvial deposits worldwide.