metamorphic
Weathered quartz-rich rock, possibly quartzite or iron-stained quartz
Quartzite (mostly SiO₂), with possible iron-oxide staining and minor feldspar/mica
AI-generated identification · may be incorrectHardness about 7 Mohs; tan-orange to brown, granular and opaque, with a dull to slightly glassy luster. The rough, massive texture suggests interlocking quartz grains rather than distinct crystal faces; cleavage is absent and specific gravity is roughly 2.6–2.7.
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Physical properties
Hardness about 7 Mohs; tan-orange to brown, granular and opaque, with a dull to slightly glassy luster. The rough, massive texture suggests interlocking quartz grains rather than distinct crystal faces; cleavage is absent and specific gravity is roughly 2.6–2.7.
Formation & geological history
Likely formed when quartz-rich sandstone was metamorphosed and recrystallized under heat and pressure, with later oxidation producing the orange-brown staining. Its precise age cannot be determined from the photograph.
Uses & applications
Quartzite is used as crushed stone, aggregate, building and paving material, and occasionally as decorative stone; attractive pieces are collected but this specimen appears common-grade.
Geological facts
Quartzite commonly rings or produces a spark when struck with steel and resists scratching by ordinary steel. Orange coloration typically reflects hematite or goethite coatings between grains or along fractures.
Field identification & locations
Look for a hard, non-cleaving rock that scratches glass and breaks across quartz grains rather than around them; acid should not fizz. Common in metamorphic mountain belts and quartz-rich sedimentary terrains worldwide.
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