metamorphic
Iron-rich quartzite or ferruginous metamorphic rock
Ferruginous quartzite, dominated by quartz (SiO₂) with hematite/goethite and minor iron oxides
AI-generated identification · may be incorrectTypically very hard (about Mohs 7), dense, reddish-brown to pink with rusty yellow streaks, and a dull to vitreous luster. Quartz grains are interlocked and show no obvious cleavage; iron oxides create the coloration and weathered patches.
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Physical properties
Typically very hard (about Mohs 7), dense, reddish-brown to pink with rusty yellow streaks, and a dull to vitreous luster. Quartz grains are interlocked and show no obvious cleavage; iron oxides create the coloration and weathered patches.
Formation & geological history
Formed when quartz-rich sandstone was metamorphosed and cemented, later enriched or stained by oxidizing iron-bearing fluids. Such rocks commonly range from Precambrian to younger metamorphic ages, depending on locality.
Uses & applications
Used locally as durable aggregate, road stone, building stone, and occasionally as an ornamental material. Attractive specimens may be collected, but this example appears commercially common.
Geological facts
The red, brown, and yellow colors generally reflect hematite, limonite, and goethite rather than copper minerals. A steel file should have difficulty scratching fresh quartz-rich surfaces.
Field identification & locations
Common in banded iron formation terrains and metamorphic belts, including India, Brazil, Australia, and Africa. Confirm with a glass-scratch test, lack of acid reaction, and a streak or magnetic test if magnetite is present.
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