mineral

Ferruginous Quartz

Quartz (Silicon Dioxide, SiO2) with iron oxide inclusions

Hardness: 7 (Mohs scale); Color: Brown, orange, or yellow due to hematite or goethite staining; Luster: Vitreous to waxy; Crystal structure: Trigonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Luster: Vitreous to waxy

Identified April 6, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or secondary sedimentary processes where iron-rich groundwater stains existing quartz crystals. This process can occur across many geological eras from the Precambrian to recent times.

Uses & applications

Primarily used as a decorative collector's specimen or lapidary material. High-quality varieties are sometimes cut into cabochons for jewelry.

Geological facts

Also known as 'Eisenkiesel' in German (meaning 'iron-pebble'). The iron content can be present as a surface coating or as internal inclusions throughout the crystal lattice.

Field identification & locations

Identify in the field by its hardness (scratches glass), conchoidal (shell-like) fracture, and the characteristic rusty-orange staining that cannot be easily washed off. Commonly found in river beds or mining tailing piles.

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