metamorphic
Weathered brown mineralized rock
Likely iron-stained quartzite or quartz-rich metamorphic rock; exact identification requires testing
AI-generated identification · may be incorrectHardness likely 6–7 Mohs, brown to gray with rusty iron-oxide staining, earthy to dull luster, granular crystalline texture, and no obvious cleavage. Irregular fracture and resistant quartz-rich patches are consistent with quartzite, though the image is inconclusive.
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Physical properties
Hardness likely 6–7 Mohs, brown to gray with rusty iron-oxide staining, earthy to dull luster, granular crystalline texture, and no obvious cleavage. Irregular fracture and resistant quartz-rich patches are consistent with quartzite, though the image is inconclusive.
Formation & geological history
Probably formed when quartz-rich sandstone was recrystallized during metamorphism, then later oxidized and weathered near the surface. Its geological age and locality cannot be determined from the photograph alone.
Uses & applications
Common quartzite is used as aggregate, building stone, paving, and decorative material; attractive specimens may be collected but usually have modest value.
Geological facts
Quartzite commonly scratches glass and does not fizz with dilute hydrochloric acid, unlike limestone. Brown coloration often comes from hematite or limonite coatings and inclusions.
Field identification & locations
Look for interlocking quartz grains, very high hardness, and a massive texture; a streak, acid, hardness, and magnification test would help distinguish it from iron-rich sandstone or altered rock. Quartzite occurs worldwide in metamorphic mountain belts.
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