metamorphic

Quartzite

Metamorphic Quartzite (SiO2)

AI-generated identification · may be incorrect

Hardness of 7 on the Mohs scale, colors range from white and gray to shades of pink, brown, and yellowish-orange due to iron oxide staining. Exhibits a vitreous to greasy luster, massive crystal structure with interlocking quartz grains, and uneven to conchoidal fracture.

Identified August 3, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed from quartz-rich sandstone or chert that has been subjected to immense heat and pressure through regional or contact metamorphism, typically taking millions of years in tectonic convergent zones.

Uses & applications

Used in construction as crushed stone for road bases, railway ballast, building facades, and decorative landscaping. High-purity quartzite is used to produce silicon metal and ferrosilicon.

Geological facts

Quartzite is extremely durable and resistant to weathering, which explains why quartz-rich mountain ridges often stand out as high peaks or ridges after surrounding softer rocks have eroded away.

Field identification & locations

Can be identified in the field by its extreme hardness (will easily scratch glass and cannot be scratched by a knife) and the sugary texture of interlocking quartz crystals visible on broken surfaces. Found worldwide in ancient mountain belts.