mineral

Iron-stained quartz

Quartz (SiO₂), likely limonite/goethite-stained

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent white to honey-brown, with vitreous to sugary luster and irregular fracture. Quartz is trigonal and lacks cleavage; brown coloration likely comes from iron oxides/hydroxides in cracks and surface coatings.

Identified September 15, 2026More mineral →

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Physical properties

Formation & geological history

Quartz commonly crystallizes from silica-rich hydrothermal fluids in veins and cavities, or precipitates in sedimentary environments. The specimen’s exact age and locality cannot be determined from the photograph.

Uses & applications

Common quartz is used in glass, ceramics, abrasives, engineered stone, and electronics; attractive pieces are sold as mineral specimens. This rough fragment has modest decorative and collecting value.

Geological facts

The rusty brown material is probably limonite or goethite rather than part of the quartz crystal structure. Strong glassy luster and resistance to scratching help distinguish quartz from calcite or feldspar.

Field identification & locations

Look for scratch resistance against ordinary glass, no obvious cleavage, and possible conchoidal fracture; a streak test and acid test can help rule out calcite. Common worldwide in quartz veins, geodes, pegmatites, and altered rocks.