metamorphic
Iron-rich quartzite or quartz-bearing metamorphic rock
Quartzite, predominantly SiO₂, with iron-oxide staining (hematite/goethite)
AI-generated identification · may be incorrectHardness about 7 Mohs; brown, rust-red, gray, and cream coloration; vitreous to dull luster; granular interlocking quartz texture with no obvious cleavage and irregular fracture. The specimen appears dense and strongly weathered or iron-stained.
Identified More metamorphic →
Explore Iron-rich quartzite or quartz-bearing metamorphic rock in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness about 7 Mohs; brown, rust-red, gray, and cream coloration; vitreous to dull luster; granular interlocking quartz texture with no obvious cleavage and irregular fracture. The specimen appears dense and strongly weathered or iron-stained.
Formation & geological history
Formed when quartz-rich sandstone was recrystallized under heat and pressure, commonly during regional mountain-building; iron-bearing fluids later produced the rusty staining. Exact geological age cannot be determined from the photograph.
Uses & applications
Used as crushed stone, road aggregate, building stone, landscaping rock, and occasionally as a decorative or lapidary material. This rough piece has modest collector value.
Geological facts
Quartzite is typically harder and more resistant to weathering than its sandstone precursor. Brown-red colors commonly result from hematite and goethite coatings or cement.
Field identification & locations
Identify it by its very hard, quartz-rich character: it should scratch glass and break across grains rather than split into sand layers; a streak test and acid test are generally non-diagnostic. Common in metamorphic belts worldwide, including the Appalachian, Rocky, and European mountain regions.
More like this
