metamorphic
Red Quartzite
Metamorphic Quartzite (rich in hematite impurities)
Hardness: 7 on Mohs scale; Color: Reddish-orange to pinkish-brown due to iron oxide (hematite); Luster: Vitreous to waxy/dull; Crystal structure: Trigonal (microcrystalline interlocked quartz grains); Cleavage: None (conchoidal or irregular fracture); Specific gravity: ~2.65
- Hardness
- 7 on Mohs scale
- Color
- Reddish-orange to pinkish-brown due to iron oxide (hematite)
- Luster
- Vitreous to waxy/dull
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Physical properties
Hardness: 7 on Mohs scale; Color: Reddish-orange to pinkish-brown due to iron oxide (hematite); Luster: Vitreous to waxy/dull; Crystal structure: Trigonal (microcrystalline interlocked quartz grains); Cleavage: None (conchoidal or irregular fracture); Specific gravity: ~2.65
Formation & geological history
Formed when quartz-rich sandstone is subjected to intense heat and pressure during regional metamorphism, causing quartz grains to recrystallize into an interconnected network. Iron oxide inclusions impart the distinctive reddish hue.
Uses & applications
Used as construction aggregate, decorative landscaping stone, dimensional stone in building facades, and occasional lapidary carving or tumbling.
Geological facts
Unlike sandstone, which breaks around individual sand grains, quartzite breaks directly through the recrystallized quartz grains. It is extremely resistant to chemical and physical weathering.
Field identification & locations
Identify by its high hardness (scratches glass easily), sugary to crystalline texture on fresh fractures, and lack of reaction with acids. Commonly found in mountainous metamorphic terrains, glacial drift, and river gravel deposits worldwide.
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