metamorphic
Quartzite (probable)
Quartzite; predominantly crystalline quartz (SiO₂)
AI-generated identification · may be incorrectTypically very hard (Mohs 7), pale gray to white, with a sugary or glassy luster and interlocking quartz grains; generally lacks cleavage and breaks irregularly. The specimen’s rough, granular texture and light color fit quartzite, though a photo cannot exclude quartz-rich sandstone or milky quartz.
Identified More metamorphic →
Explore Quartzite (probable) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Typically very hard (Mohs 7), pale gray to white, with a sugary or glassy luster and interlocking quartz grains; generally lacks cleavage and breaks irregularly. The specimen’s rough, granular texture and light color fit quartzite, though a photo cannot exclude quartz-rich sandstone or milky quartz.
Formation & geological history
Formed when quartz-rich sandstone is recrystallized under heat and pressure during regional metamorphism, commonly from Precambrian to younger mountain-building events. It occurs in metamorphic belts and resistant ridges.
Uses & applications
Used as crushed stone, aggregate, building and decorative stone; attractive pieces are collected but usually have modest value.
Geological facts
Quartzite commonly resists weathering more strongly than surrounding rocks, forming prominent ridges, cliffs, and rounded stream cobbles.
Field identification & locations
Identify it by scratching glass, lack of obvious layered grains, and a granular crystalline texture; hydrochloric acid should not fizz unless carbonate minerals are present. Common worldwide, including the Appalachians, Rocky Mountains, India, Brazil, and Scandinavia.
More like this
