mineral
Quartz Pebble (Milky Quartz / Chalcedony)
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 7 on Mohs scale; Color: semi-translucent grayish-white with faint iron oxide staining; Luster: vitreous to waxy; Cleavage: none (conchoidal fracture); Specific gravity: ~2.65
- Hardness
- 7 on Mohs scale
- Luster
- vitreous to waxy
Identified More mineral →
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Physical properties
Hardness: 7 on Mohs scale; Color: semi-translucent grayish-white with faint iron oxide staining; Luster: vitreous to waxy; Cleavage: none (conchoidal fracture); Specific gravity: ~2.65
Formation & geological history
Formed through hydrothermal precipitation or crystallization within igneous pegmatites or metamorphic veins. This specific specimen has been heavily rounded and smoothed by mechanical fluvial or beach erosion.
Uses & applications
Common quartz pebbles are used in landscaping, aggregate, tumbling for decorative crafts, and as raw materials for silicon or glass production.
Geological facts
Quartz is the second most abundant mineral in the Earth's continental crust. Its high hardness and lack of cleavage make it exceptionally durable against weathering, which is why it often survives as rounded pebbles in stream beds long after host rocks have eroded away.
Field identification & locations
Identify in the field by its ability to readily scratch glass and steel (hardness 7), irregular waxy to vitreous surfaces, lack of cleavage planes, and semi-translucent body. Extremely common in river gravels, glacial tills, and shorelines worldwide.
