mineral

Ferruginous Quartz

Quartz with Iron Oxide inclusions (SiO2 + Fe2O3)

Hardness: 7 (Mohs scale); Color: Rusty red, brown, and yellowish creamy white; Luster: Vitreous to earthy; Crystal Structure: Hexagonal (Trigonal); Cleavage: Indistinct/Conchoidal.

Hardness: 7 (Mohs scale)
Color: Rusty red, brown, and yellowish creamy white
Luster: Vitreous to earthy

Identified March 19, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Rusty red, brown, and yellowish creamy white; Luster: Vitreous to earthy; Crystal Structure: Hexagonal (Trigonal); Cleavage: Indistinct/Conchoidal.

Formation & geological history

Formed through hydrothermal processes where silica-rich fluids precipitate into cavities. The red coloration comes from hematite or goethite staining (iron oxide) during or after the quartz crystal growth.

Uses & applications

Primarily used as a decorative specimen for mineral collectors. In industrial forms, common quartz is used for glassmaking and electronics, but ferruginous specimens are mostly metaphysical or aesthetic items.

Geological facts

Also known as 'Eisenkiesel' (German for iron-pebble). The iron can be either a coating on the surface of the crystals or included within the crystal lattice itself, giving it a permanent 'rusty' appearance.

Field identification & locations

Identify in the field by its hardness (it will scratch glass) and its association with iron-rich mining districts or sedimentary 'red beds.' Commonly found in pockets of limestone or volcanic rock.

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