metamorphic
Quartzite with Chlorite staining
Metamorphic Quartzite (SiO2 with Chlorite inclusions)
Hardness: 7 on Mohs scale; Color: Grayish-white with green surface staining; Luster: Vitreous to dull; Crystal structure: Non-foliated, granular; Cleavage: None (conchoidal fracture).
- Hardness
- 7 on Mohs scale
- Color
- Grayish-white with green surface staining
- Luster
- Vitreous to dull
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Physical properties
Hardness: 7 on Mohs scale; Color: Grayish-white with green surface staining; Luster: Vitreous to dull; Crystal structure: Non-foliated, granular; Cleavage: None (conchoidal fracture).
Formation & geological history
Formed through the regional metamorphism of quartz-rich sandstone under intense heat and pressure. The green coloration is likely due to the presence of chlorite minerals or lichen growth on the surface.
Uses & applications
Used in construction as road ballast, gravel, or building stone. Pure varieties are used to produce silica sand for glassmaking.
Geological facts
Quartzite is so tough that it usually breaks through the quartz grains rather than along their boundaries, unlike sandstone. It is one of the most durable rocks on the Earth's surface.
Field identification & locations
Identify by its extreme hardness (cannot be scratched by a steel knife) and sugary, granular texture. Commonly found in folded mountain ranges. Collectors look for pieces with interesting mineral inclusions.
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