metamorphic
Weathered quartz-rich metamorphic rock, possibly quartzite
Quartzite (mostly SiO₂), with probable iron-oxide staining and minor feldspar/mica
AI-generated identification · may be incorrectHardness about 7 Mohs; pale gray, tan, and rusty brown with a glassy to dull luster and granular, interlocking quartz texture. No obvious cleavage; brown coloration likely comes from hematite/limonite, while dark patches may be mica or other accessory minerals.
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Physical properties
Hardness about 7 Mohs; pale gray, tan, and rusty brown with a glassy to dull luster and granular, interlocking quartz texture. No obvious cleavage; brown coloration likely comes from hematite/limonite, while dark patches may be mica or other accessory minerals.
Formation & geological history
Likely formed when quartz-rich sandstone was recrystallized under heat and pressure, commonly during regional metamorphism; its precise geological age cannot be determined from the image. Surface weathering produced the orange-brown iron staining and rough texture.
Uses & applications
Quartzite is used as crushed stone, aggregate, riprap, building stone, countertops, and decorative slabs; attractive specimens may be collected but this example appears ordinary.
Geological facts
Quartzite commonly breaks across grains rather than around them, unlike sandstone, and can be harder than a steel knife. The image does not provide enough detail for a definitive identification; it could also be strongly silicified sandstone or weathered quartz-bearing rock.
Field identification & locations
Look for grains that are fused into a hard mass, resistance to scratching by steel, and little or no reaction to dilute hydrochloric acid. Common worldwide in metamorphic belts, especially near former sandstone formations.
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