metamorphic

Quartzite pebble

Quartzite, composed predominantly of recrystallized quartz (SiO₂)

AI-generated identification · may be incorrect

Hardness about 7 Mohs; tan to brown, with a dull to subtly vitreous luster and a granular texture. Quartz grains are interlocked; no obvious cleavage, and specific gravity is about 2.65.

Identified September 29, 2026More metamorphic →

Explore Quartzite pebble in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness about 7 Mohs; tan to brown, with a dull to subtly vitreous luster and a granular texture. Quartz grains are interlocked; no obvious cleavage, and specific gravity is about 2.65.

Formation & geological history

Forms when quartz-rich sandstone is fused and recrystallized under heat and pressure during metamorphism. It may be hundreds of millions to billions of years old; the image alone cannot determine its age or source.

Uses & applications

Used as a durable decorative stone, landscaping material, and aggregate; attractive pieces are collected, though this specimen is not gem quality.

Geological facts

Quartzite is much harder than its sandstone precursor and typically fractures through grains rather than around them.

Field identification & locations

The rounded shape suggests water or sediment transport. Identify it by its hardness, quartz-rich granular surface, and lack of fizz with dilute acid; quartzite occurs worldwide in metamorphic terrains and river gravels.