metamorphic

Quartzite

Metamorphic Quartzite (SiO2)

AI-generated identification · may be incorrect

Hardness of 7 on the Mohs scale, colors ranging from white and gray to shades of pink, yellow, or brown, vitreous to greasy luster, non-foliated crystalline structure, conchoidal fracture.

Identified August 1, 2026More metamorphic →

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Physical properties

Hardness of 7 on the Mohs scale, colors ranging from white and gray to shades of pink, yellow, or brown, vitreous to greasy luster, non-foliated crystalline structure, conchoidal fracture.

Formation & geological history

Formed when quartz-rich sandstone is subjected to high heat and pressure, typically through tectonic compression in orogenic belts over millions of years.

Uses & applications

Used in construction, railroad ballast, decorative aggregates, countertops, and occasionally for carving or lapidary work.

Geological facts

Quartzite is extremely durable and weather-resistant, which is why ridges formed of quartzite often persist as prominent hills or mountain crests.

Field identification & locations

Identified by its hard, interlocking quartz grains that do not fizz with acid and cannot be scratched by a steel knife. Commonly found in mountainous regions worldwide.