metamorphic
Quartzite
Metamorphic Quartz Sandstone
Hardness: 7 on Mohs scale, Color: White to grey, sometimes pink or yellowish due to iron oxides, Luster: Vitreous to greasy, Crystal structure: Trigonal (microcrystalline quartz grains), Cleavage: None (fractures conchoidally), Specific gravity: 2.65
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Physical properties
Hardness: 7 on Mohs scale, Color: White to grey, sometimes pink or yellowish due to iron oxides, Luster: Vitreous to greasy, Crystal structure: Trigonal (microcrystalline quartz grains), Cleavage: None (fractures conchoidally), Specific gravity: 2.65
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone under intense heat and pressure, typically occurring during mountain-building tectonic events (orogeny).
Uses & applications
Used in construction, as crushed stone for road bases, railway ballast, manufacturing of silica bricks, and occasionally as an ornamental stone or decorative aggregate.
Geological facts
Quartzite is extremely durable and resistant to chemical weathering, which is why mountains made of quartzite often form the highest ridges and peaks in many mountain ranges.
Field identification & locations
Can be identified by its inability to be scratched by a knife or glass, its granular sugary texture on broken surfaces, and the fact that it does not fizz with acid. Found worldwide in ancient orogenic belts.
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