mineral

Iron-stained quartz with limonite/goethite coating

Quartz (SiO₂) with iron oxyhydroxides, chiefly goethite (α-FeO(OH)) and/or limonite

AI-generated identification · may be incorrect

Quartz is Mohs 7, vitreous, commonly white to translucent; the rusty brown-yellow coating is earthy to glossy and variable in hardness. Quartz has a trigonal crystal structure and no cleavage, breaking conchoidally; the specimen appears massive rather than well-crystallized.

Identified October 10, 2026More mineral →

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Physical properties

Formation & geological history

Quartz formed from silica-rich fluids or within a quartz vein; later iron-rich fluids or weathering deposited yellow-brown iron oxides. Exact age and locality cannot be determined from the image.

Uses & applications

Mostly a collector specimen; iron-stained quartz is also used decoratively, while clear quartz has broad industrial uses.

Geological facts

The yellow-brown color comes from iron compounds coating or staining the quartz, not from quartz itself.

Field identification & locations

Look for hard, glassy quartz areas that resist scratching by a steel knife, alongside rusty coatings; common in weathered veins and iron-rich settings worldwide. The photo does not establish a precise variety or source.