metamorphic
Iron-stained quartz vein rock
Milky quartz (SiO₂) with limonite/goethite iron oxides, possibly in altered host rock
AI-generated identification · may be incorrectWhite to translucent, massive quartz with yellow-brown to reddish earthy iron-oxide staining; vitreous to dull luster, conchoidal fracture, no cleavage, Mohs hardness about 7, and specific gravity near 2.65. The dark matrix may be weathered schist, granite, or another host rock.
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Physical properties
White to translucent, massive quartz with yellow-brown to reddish earthy iron-oxide staining; vitreous to dull luster, conchoidal fracture, no cleavage, Mohs hardness about 7, and specific gravity near 2.65. The dark matrix may be weathered schist, granite, or another host rock.
Formation & geological history
Likely formed when silica-rich hydrothermal fluids filled fractures, depositing quartz; later oxidation of iron-bearing minerals produced the golden-brown limonite/goethite coatings. The exact age and host rock cannot be determined from the image.
Uses & applications
Commonly collected as a field specimen and occasionally used as decorative stone or crushed aggregate; generally unsuitable for faceted gemstones because the quartz is opaque and fractured.
Geological facts
Iron oxides can create attractive gold, orange, and red patterns but are not native gold. A streak test and hardness test help distinguish it from softer yellow minerals.
Field identification & locations
Common in hydrothermal veins, fault zones, metamorphic terrains, and weathered mineralized areas worldwide. Quartz should scratch glass, while the brown coating typically leaves a yellow-brown streak and is much softer.
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