mineral

Ferruginous Quartz (Iron-stained Quartz)

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Hardness: 7 on Mohs scale; Color: Milky white with reddish-brown staining; Luster: Vitreous to greasy; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Milky white with reddish-brown staining
Luster: Vitreous to greasy

Identified March 22, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or as a secondary precipitate in silica-rich fluids. The reddish-brown coloration is caused by iron oxide (Hematite or Limonite) leaching into fractures or coating the grain boundaries during or after the quartz's formation.

Uses & applications

Used primarily as decorative landscaping stone, in lapidary work for cabochons, and as a raw material in the glass and silicon industry if high purity quartz is extracted.

Geological facts

Iron-stained quartz is often mistaken for rose quartz, but unlike rose quartz which has internal coloration, ferruginous quartz is colored by external iron minerals sitting in surface cracks. It is one of the most common minerals found on the Earth's surface.

Field identification & locations

Identify in the field by its inability to be scratched by steel, its waxy texture, and the distinct 'rusty' appearance in cracks. It is ubiquitous globally and often found in mountain regions or dry riverbeds.

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