metamorphic
Likely weathered quartzite or quartz-rich pebble
Quartzite; predominantly crystalline SiO₂
AI-generated identification · may be incorrectHardness about 7 Mohs; tan to golden-brown, opaque, with a dull to subtly vitreous luster and massive granular texture. It lacks obvious cleavage and appears naturally rounded and weathered.
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Physical properties
Hardness about 7 Mohs; tan to golden-brown, opaque, with a dull to subtly vitreous luster and massive granular texture. It lacks obvious cleavage and appears naturally rounded and weathered.
Formation & geological history
Quartzite forms when quartz-rich sandstone is recrystallized during metamorphism, commonly in mountain-building zones; its exact geological age cannot be determined from the image. The surface color likely reflects iron-oxide staining and weathering.
Uses & applications
Used as durable aggregate, paving and building stone, landscaping rock, and occasionally as a lapidary or collectible specimen. This small, ordinary piece has minimal commercial value.
Geological facts
Quartzite commonly breaks across quartz grains rather than along bedding and can scratch ordinary glass. Similar-looking tan rocks may instead be chert, quartz, jasper, or iron-stained sandstone.
Field identification & locations
Test with a steel knife and glass: genuine quartz-rich material resists a knife and can scratch glass, though this is not diagnostic alone. Common in mountain belts and stream gravels worldwide; a fresh broken surface should look sugary and quartz-rich.
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