metamorphic

Rounded pebble, likely quartzite

Quartzite (predominantly recrystallized quartz, SiO₂); identification is tentative from the image

AI-generated identification · may be incorrect

Pale gray-beige with a rusty iron-oxide stain and a dull to slightly glassy surface. Quartz has Mohs hardness 7, trigonal crystal structure, no cleavage, and specific gravity about 2.65; the pebble’s rounded shape obscures its texture.

Identified October 4, 2026More metamorphic →

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Physical properties

Formation & geological history

Quartzite forms when quartz-rich sandstone is metamorphosed under heat and pressure, commonly during mountain building. Its exact geological age and source cannot be determined from the photograph.

Uses & applications

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

Geological facts

Quartz grains in true quartzite are fused together, making it notably resistant to weathering and often harder to break across grain boundaries than sandstone.

Field identification & locations

The smooth, rounded form suggests transport by water or other abrasion; look for a hard surface and interlocking quartz grains to distinguish quartzite from sandstone. Quartzite occurs worldwide, but this individual’s locality is unknown.