metamorphic
Weathered quartz-rich metamorphic rock, likely quartzite
Quartzite; predominantly quartz (SiO₂), possibly with feldspar, mica, and iron-oxide staining
AI-generated identification · may be incorrectHardness about 7 Mohs; pale gray, white, and rusty brown, with a granular sugary texture and dull to glassy luster. Quartzite lacks prominent cleavage and commonly breaks irregularly; the image is insufficient for definitive identification.
Identified More metamorphic →
Explore Weathered quartz-rich metamorphic rock, likely quartzite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness about 7 Mohs; pale gray, white, and rusty brown, with a granular sugary texture and dull to glassy luster. Quartzite lacks prominent cleavage and commonly breaks irregularly; the image is insufficient for definitive identification.
Formation & geological history
Forms when quartz-rich sandstone is recrystallized under heat and pressure during regional metamorphism, commonly in Precambrian to younger mountain belts. Surface iron oxidation produces the brown staining and weathered rind.
Uses & applications
Used as crushed aggregate, road stone, building stone, landscaping rock, and occasionally countertops or decorative slabs. Ordinary weathered pieces have little commercial value.
Geological facts
Quartzite is generally harder and more resistant to weathering than its sandstone precursor. A useful test is that a steel nail usually will not scratch fresh quartzite, whereas quartz-rich sandstone may crumble or scratch more readily.
Field identification & locations
Common in metamorphic terrains, river gravels, glacial deposits, and mountain foothills worldwide. Look for fused quartz grains and a lack of obvious sand-grain boundaries; acid reaction should be absent unless carbonate minerals are present.
More like this
