metamorphic

Quartzite

Quartzite (Metamorphic Quartz Arenite)

AI-generated identification · may be incorrect

Hardness of 7 on the Mohs scale, white to grey color with darker mineral speckles, vitreous to greasy luster, non-foliated massive crystal structure, concoidal fracture, specific gravity around 2.65.

Identified August 2, 2026More metamorphic →

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Physical properties

Hardness of 7 on the Mohs scale, white to grey color with darker mineral speckles, vitreous to greasy luster, non-foliated massive crystal structure, concoidal fracture, specific gravity around 2.65.

Formation & geological history

Formed from quartz-rich sandstone (quartz arenite) under high temperature and pressure conditions during regional or contact metamorphism, often over millions of years.

Uses & applications

Used in construction, as crushed stone for road bases, railway ballast, dimension stone, and occasionally in decorative landscaping.

Geological facts

Unlike sandstone which breaks around sand grains, quartzite breaks straight through the quartz grains because of the intense heat and pressure fusing them tightly together.

Field identification & locations

Identified by its high hardness (scratches glass easily), lack of effervescence with acid, and the fused sugary texture visible on broken surfaces. Common worldwide in mountainous regions and ancient cratons.