igneous
Quartz-rich river pebble
Likely milky quartz or quartzite; predominantly silicon dioxide (SiO₂)
AI-generated identification · may be incorrectRounded, opaque cream-to-tan pebble with brown weathering or iron staining and a dull to vitreous sheen. Quartz has Mohs hardness 7, trigonal crystal structure, no cleavage, and specific gravity about 2.65; quartzite shares similar properties.
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Physical properties
Rounded, opaque cream-to-tan pebble with brown weathering or iron staining and a dull to vitreous sheen. Quartz has Mohs hardness 7, trigonal crystal structure, no cleavage, and specific gravity about 2.65; quartzite shares similar properties.
Formation & geological history
The pebble was rounded by transport in water or sediment; it may be a fragment of quartz vein or quartzite, whose original formation could be much older than its river-worn shape. The photo alone cannot determine its precise rock type or age.
Uses & applications
Common quartz pebbles are used in landscaping, aggregate, and decorative crafts; attractive pieces may be kept as curiosities.
Geological facts
Quartz is among Earth’s most abundant minerals and resists weathering, helping it persist as rounded pebbles in streams and gravel beds.
Field identification & locations
Look for hardness (it should scratch glass), lack of cleavage, and a waxy-to-glassy fracture; quartzite typically has interlocking grains. Quartz-rich pebbles occur worldwide in river gravels and beaches.
