mineral

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Clear to milky white with brownish-orange rust/iron staining; Luster: Vitreous (glassy); Crystal Structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Clear to milky white with brownish-orange rust/iron staining
Luster: Vitreous (glassy)

Identified July 3, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal fluids cooling in veins or cavities within various rock types. The iron staining occurs when the specimen is exposed to oxygen and water-containing iron oxides during weathering.

Uses & applications

Used widely in glassmaking, electronics (piezoelectric properties), abrasives, and as a component in construction concrete. Specimens like this are common for beginner collectors.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is clear, but tiny inclusions of iron, as seen here, give it a 'rusty' appearance characteristic of surface-weathered specimens.

Field identification & locations

Identify in the field by its ability to scratch glass and lack of cleavage. Look for glassy luster on broken surfaces. It is found globally, particularly in areas with igneous or metamorphic outcrops.