metamorphic
Iron-stained quartz-rich rock, likely sandstone or quartzite
Quartzite (SiO₂), possibly ferruginous sandstone
AI-generated identification · may be incorrectTan-orange, granular and earthy with rusty iron-oxide staining; quartz is Mohs 7, vitreous to dull, with no cleavage and conchoidal fracture. The specimen appears fine- to medium-grained and compact, though its texture could indicate weakly cemented sandstone.
Identified More metamorphic →
Explore Iron-stained quartz-rich rock, likely sandstone or quartzite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Tan-orange, granular and earthy with rusty iron-oxide staining; quartz is Mohs 7, vitreous to dull, with no cleavage and conchoidal fracture. The specimen appears fine- to medium-grained and compact, though its texture could indicate weakly cemented sandstone.
Formation & geological history
Quartzite forms when quartz-rich sandstone is metamorphosed under heat and pressure, recrystallizing grains; ferruginous sandstone forms by iron-oxide cementation. Precise age and origin cannot be determined from the photograph.
Uses & applications
Used as crushed aggregate, road stone, building and decorative stone; attractive pieces may be collected, but this specimen has limited gem value.
Geological facts
Orange and brown colors commonly come from hematite or goethite coatings between quartz grains. A glass-scratch test can help confirm abundant quartz.
Field identification & locations
Common in metamorphic terrains and sandstone regions worldwide, including the Appalachian Mountains, western United States, Brazil, and Australia. Quartzite feels hard and sugary-granular; sandstone commonly crumbles or releases grains when scratched.
More like this
