metamorphic

Rounded river pebble, likely quartzite

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

AI-generated identification · may be incorrect

Olive-brown, mottled, smooth and water-worn, with a subdued vitreous sheen. Quartz has Mohs hardness 7, hexagonal crystal structure and no cleavage; specific gravity is about 2.65.

Identified October 13, 2026More metamorphic →

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Physical properties

Olive-brown, mottled, smooth and water-worn, with a subdued vitreous sheen. Quartz has Mohs hardness 7, hexagonal crystal structure and no cleavage; specific gravity is about 2.65.

Formation & geological history

Quartz-rich sandstone metamorphosed under heat and pressure into interlocking quartz grains, then rounded by transport in water. Its age cannot be determined from appearance alone.

Uses & applications

Quartzite is used as building and paving stone, aggregate, and decorative stone; this small pebble is mainly a natural-history or collecting specimen.

Geological facts

Quartzite can resemble quartz-rich sandstone, but its grains are fused together and it typically breaks across grains rather than around them.

Field identification & locations

Look for hardness sufficient to scratch glass and a granular, quartz-rich texture; the smooth shape indicates abrasion in a stream or on a shore. Quartzite occurs worldwide in metamorphic terrains and river deposits.