metamorphic
Likely quartzite pebble
Quartzite, predominantly crystalline SiO₂
AI-generated identification · may be incorrectSmall rounded, tan-brown pebble with a dull to slightly vitreous luster and pale fracture/vein lines. Quartzite hardness is about 7 Mohs, with no cleavage, granular interlocking crystals, and specific gravity near 2.65; the photograph is insufficient to confirm texture or composition.
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Physical properties
Small rounded, tan-brown pebble with a dull to slightly vitreous luster and pale fracture/vein lines. Quartzite hardness is about 7 Mohs, with no cleavage, granular interlocking crystals, and specific gravity near 2.65; the photograph is insufficient to confirm texture or composition.
Formation & geological history
Formed when quartz-rich sandstone is recrystallized under heat and pressure during metamorphism; ages vary widely depending on the source terrain. The rounded shape indicates later transport and abrasion in a stream, beach, or glacial deposit.
Uses & applications
Commonly used as durable aggregate, paving stone, landscaping material, and decorative rock; attractive pieces may be collected or polished, but this specimen has little commercial value.
Geological facts
Quartzite commonly breaks across grains rather than around them, unlike weakly cemented sandstone. Brown coloration is likely caused by iron-oxide staining.
Field identification & locations
Look for a sugary crystalline texture, very high hardness, and resistance to scratching by a steel knife; quartz-rich sandstone may crumble or show distinct sand grains. Common in stream gravels and metamorphic mountain belts worldwide.
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