metamorphic
Quartz-rich metamorphic rock, likely quartzite
Quartzite; predominantly crystalline quartz (SiO₂), possibly with feldspar or mica
AI-generated identification · may be incorrectTypically white to cream, granular, and glassy to sugary with no obvious cleavage; quartz has Mohs hardness 7, vitreous luster, and specific gravity about 2.65. The specimen appears to contain a darker tan-brown band or inclusion, possibly iron staining or mica-rich material.
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Physical properties
Typically white to cream, granular, and glassy to sugary with no obvious cleavage; quartz has Mohs hardness 7, vitreous luster, and specific gravity about 2.65. The specimen appears to contain a darker tan-brown band or inclusion, possibly iron staining or mica-rich material.
Formation & geological history
Forms when quartz-rich sandstone is recrystallized under heat and pressure during regional metamorphism, commonly during mountain-building; its exact geological age cannot be determined from the image. It commonly occurs in metamorphic belts and resistant stream gravels.
Uses & applications
Used as crushed stone, aggregate, building stone, countertops, and decorative material; attractive pieces may be collected or polished, though this small specimen has limited commercial value.
Geological facts
Quartzite is generally tougher and more resistant to weathering than its sandstone precursor. It can resemble marble, but quartzite is harder and does not effervesce with dilute acid.
Field identification & locations
Identify it by its gritty crystalline texture, lack of visible sand grains, and ability to scratch glass; acid testing is usually negative. Common sources include the Appalachian Mountains, Rocky Mountains, Brazil, India, and Scandinavia.
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