metamorphic

Quartz-rich metamorphic pebble, likely quartzite

Quartzite, composed predominantly of quartz (SiO₂)

AI-generated identification · may be incorrect

Pale gray-white, coarse crystalline texture with a vitreous to dull luster; quartz hardness is 7 Mohs, with no cleavage and irregular fracture. The rounded shape and surface shine suggest it has been water-worn and possibly polished.

Identified October 4, 2026More metamorphic →

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Physical properties

Formation & geological history

Quartzite forms when quartz-rich sandstone is recrystallized by heat and pressure; its age depends on the source rock and metamorphic event. The image alone cannot establish its precise origin or age.

Uses & applications

Quartzite is used as building and paving stone, aggregate, and decorative material; this rounded specimen is mainly suitable for display or collecting.

Geological facts

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

Field identification & locations

Look for interlocking quartz grains and a hard, glassy appearance; it can resemble marble but does not fizz with dilute acid. Quartzite occurs worldwide in metamorphic terrains and river deposits.