mineral

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: Transparent to tan with dark brown/black iron crusting, Luster: Vitreous (glassy) to waxy, Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified April 12, 2026More mineral →

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Physical properties

Formation & geological history

Formed through hydrothermal processes or igneous precipitation. Quartz is a major component of earth's crust and can be found in a wide variety of geological ages and environments, from volcanic veins to sedimentary river beds.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, and as a semi-precious gemstone in jewelry when high quality. Common specimens are used for landscaping or as base materials.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is clear, but impurities like iron (seen here) can turn it yellow, brown, or black.

Field identification & locations

Identify in the field by its inability to be scratched by steel, its glassy interior, and lack of cleavage planes. It often breaks with curved, shell-like (conchoidal) surfaces. Found nearly everywhere on the Earth's surface.