metamorphic

Quartzite

Quartzite (Metamorphic rock composed primarily of quartz)

AI-generated identification · may be incorrect

Hardness of 7 on the Mohs scale, color typically white to gray (sometimes pink or red due to iron impurities), vitreous to greasy luster, non-foliated crystalline structure, and conchoidal fracture.

Identified August 5, 2026More metamorphic →

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Physical properties

Hardness of 7 on the Mohs scale, color typically white to gray (sometimes pink or red due to iron impurities), vitreous to greasy luster, non-foliated crystalline structure, and conchoidal fracture.

Formation & geological history

Formed when quartz-rich sandstone is subjected to high heat and pressure associated with tectonic compression, usually in mountain-building processes.

Uses & applications

Used in construction, railroad ballast, decorative aggregates, wall cladding, and sometimes in countertops and monuments.

Geological facts

Quartzite is extremely durable and resistant to chemical weathering, which is why quartz-rich rocks often survive as pebbles and boulders long after other minerals have eroded away.

Field identification & locations

Can be identified by its inability to be scratched by steel, its lack of effervescence with acid, and the fused quartz grains visible under a hand lens. Commonly found globally in ancient mountain belts.