mineral

Iron-stained quartz-bearing rock

Quartz-rich limonite/goethite specimen; exact identification requires testing

AI-generated identification · may be incorrect

Brown to reddish-brown, earthy to submetallic surfaces with white translucent quartz. Quartz has Mohs hardness 7 and vitreous luster; iron oxides are typically softer, opaque, and earthy, with no obvious cleavage.

Identified September 16, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed by weathering and oxidation of iron-bearing sulfides or other rocks, leaving limonite/goethite around quartz veins or fragments. This is generally a near-surface, relatively young weathering product rather than a distinct age-diagnostic rock.

Uses & applications

Primarily a teaching or collecting specimen; iron oxides are ores of iron and pigments, while associated quartz is used in glass, ceramics, abrasives, and jewelry.

Geological facts

The brown coloration commonly comes from hydrated iron oxides, especially limonite, while darker areas may contain goethite or hematite. A streak test can distinguish components: iron oxides usually leave yellow-brown to reddish-brown streaks, whereas quartz leaves none.

Field identification & locations

Common in oxidized zones, gossans, quartz veins, and iron-rich soils worldwide. Check for white quartz, earthy brown coating, lack of strong cleavage, and possible magnetism; a hardness and streak test would improve identification.