metamorphic
Iron-stained quartzite or quartz-rich sandstone
Quartzite, predominantly SiO₂, with iron-oxide staining
AI-generated identification · may be incorrectTan-orange, opaque to slightly translucent, uneven granular texture, and dull to sugary vitreous luster. Quartz has Mohs hardness ~7, no cleavage, and typical specific gravity around 2.6; the rough shape and lighting limit certainty.
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Physical properties
Tan-orange, opaque to slightly translucent, uneven granular texture, and dull to sugary vitreous luster. Quartz has Mohs hardness ~7, no cleavage, and typical specific gravity around 2.6; the rough shape and lighting limit certainty.
Formation & geological history
Likely formed when quartz-rich sandstone was compacted and metamorphosed, with later weathering producing orange-brown hematite or limonite staining. Quartzite commonly ranges from Precambrian to younger geologic ages and forms in mountain belts.
Uses & applications
Used as crushed stone, landscaping aggregate, building stone, and occasionally as a decorative specimen. This ordinary piece has little jewelry value unless it contains attractive crystalline quartz or unusual patterns.
Geological facts
The orange color is usually iron oxide rather than the primary mineral. It may also be strongly cemented sandstone or iron-stained quartz; a photograph alone cannot distinguish these confidently.
Field identification & locations
Test an inconspicuous edge with a steel knife: quartz-rich material should resist scratching, while a streak test on unglazed porcelain may show little or reddish-brown powder. Common in metamorphic terrains, sandstone-derived outcrops, and gravel deposits.
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