igneous
Quartz-rich pebble, possibly vein quartz with iron/manganese staining
Predominantly quartz (SiO₂); exact rock type cannot be determined from the image alone
AI-generated identification · may be incorrectRounded, cream-to-tan and gray pebble with dark staining and a dull to weakly vitreous luster. Quartz has Mohs hardness 7, trigonal crystal structure, no cleavage, and specific gravity about 2.65; the pictured pebble appears massive rather than visibly crystalline.
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Physical properties
Rounded, cream-to-tan and gray pebble with dark staining and a dull to weakly vitreous luster. Quartz has Mohs hardness 7, trigonal crystal structure, no cleavage, and specific gravity about 2.65; the pictured pebble appears massive rather than visibly crystalline.
Formation & geological history
Likely formed as quartz-rich material in a vein or quartz-bearing rock, then rounded by transport in water. Its geological age and precise formation setting cannot be established visually.
Uses & applications
Commonly collected as a natural pebble or used decoratively; quartz is also important in glass, electronics, and construction materials.
Geological facts
Quartz is one of Earth’s most abundant minerals and resists weathering, allowing it to persist as rounded stream and beach pebbles.
Field identification & locations
Look for hardness, lack of cleavage, and a glassy appearance on fresh breaks; dark patches may be iron- or manganese-rich coatings. Quartz pebbles occur widely in river gravels and coastal deposits.
