metamorphic
Quartzite
Metamorphic Quartzite (SiO2)
Hardness of 7 on the Mohs scale, colors range from white to gray, yellowish, or brown due to iron oxide impurities. It has a vitreous to greasy luster, massive crystal structure with interlocking quartz grains, and conchoidal fracture. Specific gravity is approximately 2.65.
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Physical properties
Hardness of 7 on the Mohs scale, colors range from white to gray, yellowish, or brown due to iron oxide impurities. It has a vitreous to greasy luster, massive crystal structure with interlocking quartz grains, and conchoidal fracture. Specific gravity is approximately 2.65.
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone or chert under high temperature and tectonic pressure, commonly found in mountain-building belts.
Uses & applications
Used in construction, as crushed stone for road bases, railway ballast, dimension stone, wall cladding, and occasionally for decorative items or countertops.
Geological facts
Quartzite is extremely durable and resistant to chemical weathering, which is why quartz-rich ridges often form prominent resistant mountain ridges and hills.
Field identification & locations
Can be identified in the field by its high hardness (scratches glass easily), lack of effervescence with acid, and the way it breaks across quartz grains rather than around them, distinguishing it from sandstone.
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