metamorphic
Weathered quartz-rich rock, possibly quartzite or vein quartz
Quartz-dominant aggregate; chiefly silicon dioxide (SiO₂), possibly quartzite with iron-oxide staining
AI-generated identification · may be incorrectHardness about 7 Mohs; white to gray with yellow-brown iron staining, dull to glassy luster, massive granular texture, and no obvious cleavage. The rounded, fractured surface suggests natural weathering rather than a crystal specimen.
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Physical properties
Hardness about 7 Mohs; white to gray with yellow-brown iron staining, dull to glassy luster, massive granular texture, and no obvious cleavage. The rounded, fractured surface suggests natural weathering rather than a crystal specimen.
Formation & geological history
Likely formed from recrystallized quartz sandstone (quartzite) or precipitated hydrothermal quartz, with later oxidation and surface weathering; exact age and origin cannot be determined from the image.
Uses & applications
Usually valued as a landscape, teaching, or lapidary specimen; quartzite can be used as aggregate, riprap, building stone, and occasionally decorative material.
Geological facts
Quartz-rich rocks commonly resist weathering, leaving rounded knobs or cobbles while softer minerals dissolve. Yellow-brown patches are typically limonite/goethite staining.
Field identification & locations
Look for glassy quartz grains, extreme scratch resistance, and lack of fizz with dilute hydrochloric acid; a steel file should not scratch it. Common in quartz veins, metamorphic terrains, river gravels, and eroded mountain regions.
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