sedimentary
Yellow Quartz / Chalcedony Pebble
SiO2 (Silicon Dioxide)
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
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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.
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