metamorphic
Weathered quartz-rich rock, possibly quartzite
Quartzite (mostly SiO₂), tentatively identified
AI-generated identification · may be incorrectHardness about 7 Mohs; pale cream-white with rusty orange iron-oxide staining, dull to sugary/vitreous luster, and no obvious cleavage. The granular texture suggests interlocking quartz crystals, though the image alone cannot exclude weathered quartz vein material or chert.
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Physical properties
Hardness about 7 Mohs; pale cream-white with rusty orange iron-oxide staining, dull to sugary/vitreous luster, and no obvious cleavage. The granular texture suggests interlocking quartz crystals, though the image alone cannot exclude weathered quartz vein material or chert.
Formation & geological history
Quartzite forms when quartz-rich sandstone is recrystallized during metamorphism, commonly during mountain-building; its age depends on the original sandstone and local tectonic history. Iron-bearing groundwater can produce the orange surface staining.
Uses & applications
Used as crushed aggregate, riprap, building stone, countertops, and decorative landscaping material; ordinary specimens have little jewelry value.
Geological facts
Quartzite is typically tougher and more resistant to weathering than its sandstone precursor. A fresh broken surface is usually distinctly sparkly and sugary rather than powdery.
Field identification & locations
Common in metamorphic terrains worldwide, including the Appalachians, Rocky Mountains, Scandinavia, and India. Check for strong resistance to scratching by steel and inability to fizz in dilute acid; a glass-scratching test supports quartz content.
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