metamorphic
Quartzite
Metamorphic Quartzite (SiO2)
Hardness of 7 on the Mohs scale, color ranges from white and grey to pink and reddish due to iron oxide impurities, vitreous to greasy luster, massive crystal structure with interlocking quartz grains, conchoidal fracture, specific gravity of 2.65.
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Physical properties
Hardness of 7 on the Mohs scale, color ranges from white and grey to pink and reddish due to iron oxide impurities, vitreous to greasy luster, massive crystal structure with interlocking quartz grains, conchoidal fracture, specific gravity of 2.65.
Formation & geological history
Formed from quartz-rich sandstone or chert under high temperature and pressure during regional or contact metamorphism. Geological age varies widely depending on the formation site, ranging from Precambrian to Cenozoic.
Uses & applications
Used in construction, as crushed stone for road bases, railway ballast, dimension stone, roofing tiles, and sometimes in manufacturing refractory bricks and ferrosilicon.
Geological facts
Quartzite is extremely resistant to chemical weathering and erosion, which is why mountains made of quartzite often stand out as prominent ridges or peaks. The iron staining in this specimen gives it a pinkish-tan hue.
Field identification & locations
Identified by its inability to be scratched by a knife or glass (hardness 7) and the lack of effervescence with hydrochloric acid. It is commonly found in mountainous regions and ancient cratons worldwide.
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