metamorphic

Quartzite

Quartzite; predominantly recrystallized quartz (SiO₂)

AI-generated identification · may be incorrect

Hardness about 7 Mohs; pale gray-white with pink, tan, and reddish iron-oxide staining; vitreous to sugary luster; interlocking quartz grains with no prominent cleavage and irregular fracture. The massive, highly resistant texture distinguishes it from ordinary sandstone.

Identified September 6, 2026More metamorphic →

Explore Quartzite in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Formed when quartz-rich sandstone was buried and metamorphosed, causing quartz grains to recrystallize and fuse; commonly Precambrian to Paleozoic in age, though formation age depends on the source terrane. The specimen appears naturally weathered and iron-stained.

Uses & applications

Used as crushed aggregate, roadstone, riprap, building stone, countertops, and decorative landscape rock; attractive pieces may be cut or polished for display.

Geological facts

Quartzite can preserve faint original bedding while developing a sugary crystalline texture. Pink and red colors typically reflect hematite or other iron-bearing mineral impurities.

Field identification & locations

Identify it by testing whether it scratches glass, examining its fused granular texture, and checking that fresh breaks pass through quartz grains rather than around sand grains. Common in mountain belts and glacial or river gravels worldwide.