metamorphic
Quartz-rich metamorphic rock, likely quartzite
Quartzite; predominantly quartz (SiO₂), with minor feldspar, mica, and iron-oxide staining
AI-generated identification · may be incorrectHardness about 7 Mohs; white to gray with yellow-brown weathering, vitreous to sugary luster, granular interlocking quartz crystals, and no obvious cleavage. The specimen appears massive and weakly foliated or heavily weathered.
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Physical properties
Hardness about 7 Mohs; white to gray with yellow-brown weathering, vitreous to sugary luster, granular interlocking quartz crystals, and no obvious cleavage. The specimen appears massive and weakly foliated or heavily weathered.
Formation & geological history
Formed when quartz-rich sandstone was recrystallized under heat and pressure during regional metamorphism; exact geological age cannot be determined from the image. Commonly occurs in mountain belts and metamorphic terrains.
Uses & applications
Used as crushed stone, aggregate, building stone, landscaping material, and occasionally countertops or decorative specimens. This rough piece has limited jewelry use unless cut and polished.
Geological facts
Quartzite commonly breaks across grains rather than around them, making it tougher than its sandstone precursor. Yellow coloration typically reflects limonite or other iron oxides.
Field identification & locations
Likely quartzite if it scratches glass and shows a sugary fracture; sandstone may crumble or reveal distinct rounded grains. Common worldwide, including the Appalachian Mountains, Rocky Mountains, India, Brazil, and Scandinavia.
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