metamorphic
Quartzite
Quartzite (SiO2 composition)
Hardness: 7 on the Mohs scale. Color: Greyish-brown with white quartz flecks and reddish iron-staining along fractures. Luster: Vitreous to dull. Texture: Granular, interlocking quartz grains with a sugary texture.
- Hardness
- 7 on the Mohs scale
- Luster
- Vitreous to dull
Identified More metamorphic →
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Physical properties
Hardness: 7 on the Mohs scale. Color: Greyish-brown with white quartz flecks and reddish iron-staining along fractures. Luster: Vitreous to dull. Texture: Granular, interlocking quartz grains with a sugary texture.
Formation & geological history
Formed through the regional or contact metamorphism of quartz-rich sandstone under intense heat and pressure, causing recrystallization of quartz grains into an interconnected lattice.
Uses & applications
Used in construction as crushed stone, road aggregate, dimension stone, railroad ballast, and decorative landscaping rock.
Geological facts
Quartzite is extremely resistant to chemical weathering and physical erosion, often forming high ridges and caprocks on mountains.
Field identification & locations
Identified by its high hardness (scratches glass and steel) and interlocking sugary crystal matrix that fractures across quartz grains rather than around them. Commonly found in mountainous regions worldwide.
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