Weathered quartzite pebble

Tan-brown, rounded, with a dull to slightly vitreous luster and a granular, fused texture. Quartz hardness is 7 Mohs; individual crystals are too fine or interlocked to show obvious cleavage. The photo alone cannot confirm the identification; a scratch test and fresh fracture would help distinguish it from quartz-rich sandstone or another pebble.

Quartzite forms when quartz-rich sandstone is recrystallized and cemented by heat and pressure during metamorphism. Its age depends on its source rock and metamorphic history, which cannot be determined from the image.

Quartzite is used as construction aggregate, paving and building stone, and sometimes decorative stone; this small, worn pebble has little commercial value.

Quartzite is typically harder and more resistant to weathering than its sandstone precursor.

Look for a hard, quartz-rich rock with interlocking grains and no easy splitting along sedimentary layers; quartzite occurs worldwide in metamorphic terrains and river or beach gravels. This specimen appears naturally rounded and iron-stained.