metamorphic

Rounded brown quartzite pebble

Quartzite, composed predominantly of quartz (SiO₂)

AI-generated identification · may be incorrect

Opaque to slightly translucent brown, with a dull to faintly vitreous luster and rounded, smooth surfaces. Quartz has Mohs hardness 7 and trigonal crystal structure; the pebble’s exact composition cannot be confirmed from the photo.

Identified October 4, 2026More metamorphic →

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Physical properties

Formation & geological history

Likely formed when quartz-rich sandstone was cemented and recrystallized during metamorphism, then rounded by transport in a river or beach environment. Its age cannot be determined visually.

Uses & applications

Primarily a hand specimen or decorative pebble; quartzite is also used as aggregate, paving, and building stone.

Geological facts

Quartzite is usually harder than the sandstone from which it formed and commonly resists weathering, allowing durable rounded pebbles to accumulate in streams and beaches.

Field identification & locations

The smooth, hard-looking brown pebble is consistent with quartzite, but other rocks can look similar; a scratch test or close inspection of its grains would help distinguish it. Quartzite occurs worldwide in metamorphic terrains and derived river deposits.