metamorphic
Likely quartz-rich metamorphic rock (quartzite)
Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with mica or feldspar
AI-generated identification · may be incorrectTypically white to gray, with a sugary to glassy luster and granular texture; quartz hardness is about Mohs 7, with no cleavage and poor-to-fair fracture. The specimen appears fine- to medium-grained and foliated or fractured, so schist or recrystallized quartz sandstone is also possible.
Identified More metamorphic →
Explore Likely quartz-rich metamorphic rock (quartzite) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Typically white to gray, with a sugary to glassy luster and granular texture; quartz hardness is about Mohs 7, with no cleavage and poor-to-fair fracture. The specimen appears fine- to medium-grained and foliated or fractured, so schist or recrystallized quartz sandstone is also possible.
Formation & geological history
Forms when quartz-rich sandstone is recrystallized under heat and pressure during regional metamorphism; ages vary widely, commonly Precambrian to Paleozoic. Exact identification and age require thin-section or chemical analysis.
Uses & applications
Used as crushed stone, aggregate, road material, building stone, and occasionally decorative material; attractive quartzite is collected but is usually modestly valuable.
Geological facts
Quartzite generally breaks across quartz grains rather than around them, unlike sandstone, and commonly scratches glass. Visible planar fabric could indicate mica-bearing quartzite or quartz-mica schist.
Field identification & locations
Common in metamorphic belts worldwide, including the Appalachians, Rocky Mountains, Alps, and many Precambrian shields. A hand lens, glass-scratch test, and acid test help distinguish it from limestone; the image alone cannot confirm the diagnosis.
More like this
