metamorphic
Weathered iron-rich quartzite or ironstone cobble
Quartzite, likely limonite/goethite-stained (SiO₂ with FeO(OH)·nH₂O)
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; yellow-brown to reddish-brown, earthy to dull luster, massive granular texture, and no obvious cleavage. The rounded form and dark iron staining indicate substantial weathering and transport.
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Physical properties
Hardness about 6.5–7 Mohs; yellow-brown to reddish-brown, earthy to dull luster, massive granular texture, and no obvious cleavage. The rounded form and dark iron staining indicate substantial weathering and transport.
Formation & geological history
Likely formed when quartz-rich sandstone was metamorphosed into quartzite, then altered by circulating oxygenated water that deposited limonite/goethite. Its precise geological age and locality cannot be determined from the photograph.
Uses & applications
Useful mainly as a landscaping, teaching, or collector specimen; iron-rich quartzite can serve as aggregate or building stone, but this small weathered cobble has little commercial value.
Geological facts
The pink-red coloration is characteristic of oxidized iron minerals rather than a pink crystal mineral. A steel file should struggle to scratch it; a streak test may produce a pale or rusty powder.
Field identification & locations
Common in stream gravels, residual soils, and eroded quartzite-bearing terrains worldwide. Confirm with a hardness test, unglazed-ceramic streak, and close inspection for sugary quartz grains; the image does not support a precise species identification.
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