mineral

Ferruginous Quartz

Iron-stained Quartz (Silicon Dioxide, SiO2 with Fe2O3 inclusions)

Hardness: 7 (Mohs scale); Color: Yellowish-brown, orange, tan; Luster: Vitreous to greasy; Crystal structure: Trigonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Yellowish-brown, orange, tan
Luster: Vitreous to greasy

Identified April 12, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Yellowish-brown, orange, tan; Luster: Vitreous to greasy; Crystal structure: Trigonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Formed through hydrothermal processes where silica-rich fluids crystallize in veins. The yellow-brown coloration is a result of iron oxide (limonite or hematite) staining or inclusions, often occurring as secondary enrichment in weathered zones.

Uses & applications

Primarily used as a lapidary material for polishing, landscaping, and as a common specimen for mineral collectors. Some varieties are used in decorative carvings.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. When iron oxide is present during formation or infiltrates cracks later, it can turn clear quartz into these 'iron-stained' or 'golden' varieties.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), lack of cleavage, and the characteristic rusty-yellow translucent appearance. Found worldwide in nearly every geological environment, especially in creek beds and mountain ranges.

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