metamorphic
Quartzite
Quartzite, composed predominantly of recrystallized quartz (SiO₂)
AI-generated identification · may be incorrectTan to brown, granular and massive with a sugary, vitreous-to-dull luster; quartz hardness is 7 Mohs, and the rock has no prominent cleavage. The visible grains and rusty patches may reflect iron oxides or minor mica/feldspar.
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Physical properties
Tan to brown, granular and massive with a sugary, vitreous-to-dull luster; quartz hardness is 7 Mohs, and the rock has no prominent cleavage. The visible grains and rusty patches may reflect iron oxides or minor mica/feldspar.
Formation & geological history
Forms when quartz-rich sandstone is recrystallized by heat and pressure during metamorphism; such rocks occur in many geological ages and mountain belts.
Uses & applications
Used as building and decorative stone, crushed aggregate, and sometimes as a lapidary material.
Geological facts
Pure quartzite is highly resistant to weathering and typically breaks across its quartz grains rather than around them.
Field identification & locations
Common in metamorphic terrains worldwide. Identify it by its interlocking quartz grains, hardness, and lack of strong layering; the photo alone cannot confirm the specimen’s exact composition.
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