Rock Identifier
Iron-stained quartz (Quartz (SiO₂), with limonite/goethite coatings) — mineral
mineral

Iron-stained quartz

Quartz (SiO₂), with limonite/goethite coatings

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent white to honey-yellow, with a vitreous to resinous luster and irregular fracture. Crystals appear massive or poorly formed; yellow-orange coloration is likely iron-oxide staining rather than an intrinsic crystal color.

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Physical properties

Hardness 7 Mohs; translucent white to honey-yellow, with a vitreous to resinous luster and irregular fracture. Crystals appear massive or poorly formed; yellow-orange coloration is likely iron-oxide staining rather than an intrinsic crystal color.

Formation & geological history

Quartz commonly precipitates from silica-rich hydrothermal fluids in veins, cavities, and weathered rocks; iron oxides formed later during surface oxidation. Its exact geological age cannot be determined from the photograph.

Uses & applications

Common quartz is used in glass, ceramics, abrasives, electronics, and engineered stone; attractive translucent pieces may be collected or used as lapidary material.

Geological facts

The orange coating likely consists of limonite, a mixture dominated by hydrated iron oxides, possibly including goethite. Quartz should resist scratching by a steel knife, while the coating may scratch or crumble more easily.

Field identification & locations

Look for glassy translucence, conchoidal fracture, and no obvious cleavage; a scratch test and streak test help distinguish it from calcite or feldspar. Common worldwide in quartz veins, pegmatites, and weathered mineralized zones.