mineral

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions

Hardness: 7 on Mohs scale; Color: Reddish-pink to brown due to iron oxide staining; Luster: Vitreous to dull; Crystal structure: Trigonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Reddish-pink to brown due to iron oxide staining
Luster: Vitreous to dull

Identified May 6, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Reddish-pink to brown due to iron oxide staining; Luster: Vitreous to dull; Crystal structure: Trigonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Formed in hydrothermal veins or as a secondary precipitate in sedimentary environments where iron-rich water interacts with quartz crystals. The reddish hue is caused by hematite or goethite coatings and inclusions.

Uses & applications

Used primarily as decorative stone, aquarium decor, and by crystal collectors for 'metaphysical' grounding purposes. Hard enough for lapidary use.

Geological facts

Also known as 'Eisenkiesel' in German, meaning iron-pebble. The red coloration is often a surface coating or inter-crystalline staining rather than a change in the chemical purity of the quartz crystal lattice itself.

Field identification & locations

Identify in the field by its high hardness (cannot be scratched by steel) and lack of cleavage. Common in desert environments and iron-producing regions. Collectors look for vibrant red hues and crystalline structures beneath the iron coating.

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