metamorphic
Iron-stained quartzite or silicified rock
Quartzite; predominantly microcrystalline quartz (SiO₂) with iron-oxide staining
AI-generated identification · may be incorrectHardness about 7; tan, cream, brown, and rusty red coloration; vitreous to dull luster; massive, nonfoliated texture with no obvious cleavage. The brown-red areas are likely limonite/goethite coatings or inclusions.
Identified More metamorphic →
Explore Iron-stained quartzite or silicified rock in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness about 7; tan, cream, brown, and rusty red coloration; vitreous to dull luster; massive, nonfoliated texture with no obvious cleavage. The brown-red areas are likely limonite/goethite coatings or inclusions.
Formation & geological history
Formed when quartz-rich sandstone was metamorphosed and recrystallized, probably during a regional mountain-building event; its exact geological age cannot be determined from the photograph. Weathering later oxidized iron-bearing impurities, producing the rusty colors.
Uses & applications
Used as durable aggregate, building stone, paving, and decorative stone; attractive polished pieces may be sold as lapidary specimens. This irregular specimen has modest commercial value unless it displays unusual patterns or provenance.
Geological facts
Quartzite commonly fractures across individual grains rather than around them, producing a hard, sugary-looking surface. Strong iron staining can make it resemble jasper, chert, or weathered quartz-bearing ore.
Field identification & locations
Common in metamorphic terrains worldwide, including the Appalachians, Rocky Mountains, Alps, India, Brazil, and Australia. Confirm with a steel-file or glass-scratch test, noting that a clean quartz-rich surface should scratch glass; avoid testing valuable specimens.
More like this
