metamorphic
Iron-stained quartz-rich rock
Likely ferruginous quartzite (quartz, SiO₂, with iron oxides/hydroxides)
AI-generated identification · may be incorrectRough, granular texture; pale tan-gray with orange-brown iron staining and a dull to slightly glassy luster. Quartz has Mohs hardness 7 and trigonal crystal structure; the specimen’s overall hardness and texture depend on its cementation and other minerals.
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Physical properties
Rough, granular texture; pale tan-gray with orange-brown iron staining and a dull to slightly glassy luster. Quartz has Mohs hardness 7 and trigonal crystal structure; the specimen’s overall hardness and texture depend on its cementation and other minerals.
Formation & geological history
Quartz-rich sandstone can be recrystallized into quartzite during metamorphism; iron-bearing fluids or weathering produce the rusty staining. Precise age and origin cannot be determined from the image.
Uses & applications
Quartzite is used as building and paving stone, aggregate, and sometimes as a decorative stone; this rough specimen is mainly suitable for collecting.
Geological facts
The orange color commonly comes from iron oxides such as hematite or goethite coating or cementing quartz grains.
Field identification & locations
Look for abundant hard quartz grains and a granular or fused texture; quartzite resists scratching by a steel knife. Similar iron-stained material occurs worldwide, but a photo cannot confirm the rock type or locality.
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