metamorphic

Quartzite

Metamorphic Quartzite (SiO2)

AI-generated identification · may be incorrect

Hardness of 7 on the Mohs scale, color ranges from white and grey to yellow, pink, and brown, vitreous to greasy luster, trigonal crystal system, conchoidal fracture, specific gravity of 2.65.

Identified August 6, 2026More metamorphic →

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Physical properties

Hardness of 7 on the Mohs scale, color ranges from white and grey to yellow, pink, and brown, vitreous to greasy luster, trigonal crystal system, conchoidal fracture, specific gravity of 2.65.

Formation & geological history

Formed from quartz-rich sandstone or chert under high temperatures and pressures associated with tectonic compression during regional metamorphism.

Uses & applications

Used in construction, as crushed stone for roadbeds, in decorative aggregates, and occasionally for countertops and sculptures.

Geological facts

Quartzite is exceptionally durable and weather-resistant, often forming prominent mountain ridges because it erodes much slower than surrounding rocks.

Field identification & locations

Can be identified in the field by its extreme hardness (scratches glass easily), inability to be scratched by a knife, and the way it fractures across quartz grains rather than around them like sandstone.