mineral

Quartz with Iron Staining

Silicon Dioxide (SiO2) with Limonite/Hematite inclusions

Hardness: 7 (Mohs scale), Color: Tan, yellow-brown, and grey, Luster: Vitreous to waxy, Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified May 13, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: Tan, yellow-brown, and grey, Luster: Vitreous to waxy, Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & geological history

Formed from silica-rich hydrothermal fluids or within igneous and metamorphic rocks. The yellow/brown coloring comes from the oxidation of iron minerals (rusting) over geological time.

Uses & applications

Common quartz is used in glassmaking, electronics (piezoelectric properties), and as an abrasive. Stained specimens are popular for amateur rock collecting and landscaping.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Iron-stained quartz is often mistaken for gold-bearing ore or 'citrine', though citrine's color is within the crystal lattice rather than a surface coating.

Field identification & locations

Identify by its ability to scratch glass and its lack of cleavage. It is found globally in riverbeds, mountains, and deserts. Collectors look for iron-stained quartz as a potential indicator of other minerals nearby.

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