metamorphic

Quartzite

Metamorphic Quartzite (SiO2)

AI-generated identification · may be incorrect

Hardness of 7 on the Mohs scale; white, gray, pink, or reddish-brown color; vitreous to greasy luster; non-foliated, granular crystal structure; lacks distinct cleavage; specific gravity of 2.65.

Identified August 2, 2026More metamorphic →

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Physical properties

Hardness of 7 on the Mohs scale; white, gray, pink, or reddish-brown color; vitreous to greasy luster; non-foliated, granular crystal structure; lacks distinct cleavage; specific gravity of 2.65.

Formation & geological history

Formed through the metamorphism of quartz sandstone or chert under high heat and pressure, typically in mountain-building events over millions of years.

Uses & applications

Used in construction, railroad ballast, decorative aggregates, dimension stone, and the production of ferrosilicon and silicon.

Geological facts

Quartzite is extremely durable and resistant to chemical weathering, which is why ridges formed of quartzite often endure as prominent mountain crests.

Field identification & locations

Can be identified by its inability to be scratched by a knife, its lack of effervescence with acid, and its sugary, interlocking quartz grain texture on fractured surfaces.