metamorphic

Brown river pebble, likely quartzite

Quartzite (quartz-rich metamorphic rock); identification is tentative from the image

AI-generated identification · may be incorrect

Rounded, opaque brown pebble with a dull to slightly waxy surface and no visible cleavage. Quartzite is mainly quartz (SiO₂), typically Mohs 7, with granular crystals; the brown color may come from iron-oxide staining.

Identified September 30, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when quartz-rich sandstone is recrystallized by heat and pressure; its age depends on the source formation. The rounded shape suggests prolonged abrasion in a river or shoreline setting.

Uses & applications

Commonly used as landscaping stone, aggregate, and decorative pebble; attractive pieces may be polished or collected.

Geological facts

Quartzite can resemble quartz-rich sandstone, but its grains are tightly fused and it is generally very hard.

Field identification & locations

Look for a hard, quartz-rich texture and grains that do not readily scratch away; quartzite occurs worldwide in metamorphic terrains and as transported stream pebbles. A photo alone cannot confirm the rock type.