metamorphic
Quartzite
Metamorphic Quartz (SiO2)
AI-generated identification · may be incorrectHardness: 7 on Mohs scale; Color: Reddish-orange, pink, tan, or grey; Luster: Vitreous to dull; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Granular texture.
- Hardness
- 7 on Mohs scale
- Color
- Reddish-orange, pink, tan, or grey
- Luster
- Vitreous to dull
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Physical properties
Hardness: 7 on Mohs scale; Color: Reddish-orange, pink, tan, or grey; Luster: Vitreous to dull; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Granular texture.
Formation & geological history
Formed through the regional metamorphism of quartz-rich sandstone. High heat and pressure cause the quartz grains to recrystallize and fuse together, forming a dense, durable rock.
Uses & applications
Used in construction as road ballast, gravel, and building stone. Highly prized as a lapidary material for tumbled stones or decorative landscaping and in glass production when high purity quartz is present.
Geological facts
Quartzite is so tough that it often breaks through the quartz grains rather than along their boundaries. It is often resistant to chemical weathering and creates prominent ridges in mountainous regions.
Field identification & locations
Look for a granular, sugary texture on fresh surfaces; it will easily scratch glass and steel. Commonly found in riverbeds as rounded cobbles or in massive outcrops in mountain ranges.
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