mineral

Ferruginous Quartz

Silicon Dioxide (SiO2) with Hematite (Fe2O3) or Limonite (FeO(OH) nH2O)

Hardness: 7 on Mohs scale. Color: Opaque to translucent red, orange, or brown. Luster: Vitreous to waxy. Crystal Structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Opaque to translucent red, orange, or brown
Luster: Vitreous to waxy

Identified June 27, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the precipitation of silica from hydrothermal fluids or groundwater in cavities and veins. The red/orange coloration is caused by the inclusion of iron oxides (hematite or limonite) during or after the crystal growth process.

Uses & applications

Used primarily by lapidaries for tumbling, carving, and cabochons. Also popular among mineral collectors and used in metaphysical practices (sometimes called 'Iron Quartz' or 'Hematoid Quartz').

Geological facts

The term 'ferruginous' comes from the Latin word 'ferrum' meaning iron. This specific type of quartz is often found in sedimentary environments where iron-rich water is prevalent, staining the quartz over millions of years.

Field identification & locations

Identify in the field by its superior hardness (cannot be scratched by a steel knife) and its grainy, crystalline texture coupled with reddish-brown staining. Frequently found in riverbeds, glacial tills, and near iron ore deposits.

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