metamorphic

Weathered quartz-rich rock, possibly quartzite

Quartzite (tentative identification; exact rock type cannot be confirmed from the image)

AI-generated identification · may be incorrect

Tan to pale gray, rough and granular with a dull to slightly sparkly luster; likely dominated by quartz (Mohs hardness 7), with no obvious cleavage. The specimen’s uneven, possibly layered texture could also indicate a quartz-rich sedimentary rock.

Identified September 28, 2026More metamorphic →

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Physical properties

Formation & geological history

Quartzite forms when quartz sandstone is recrystallized by heat and pressure during metamorphism; its age depends on the source rock and metamorphic event and cannot be determined from appearance alone.

Uses & applications

Quartzite is used as crushed stone, road aggregate, and decorative building stone; distinctive pieces may be kept as educational or collection specimens.

Geological facts

Quartz-rich rocks can look similar in hand-sized photographs, and a fresh broken surface or simple hardness test is often needed to distinguish quartzite from sandstone.

Field identification & locations

Look for interlocking quartz grains and a very hard surface that scratches glass; quartzite commonly occurs in metamorphic mountain belts. Estimated value: about $0–$10 for an ordinary loose specimen.