mineral

Ferruginous Quartz (Iron-stained Quartz)

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Hardness: 7 on Mohs scale; Color: Clear to milky white with orange, red, or brown staining; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (Trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Clear to milky white with orange, red, or brown staining
Luster: Vitreous (glassy)

Identified March 22, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or pegmatites where silica-rich fluids cool. The orange/red coloration occurs when iron-bearing groundwater or hydrothermal fluids deposit iron oxides (like hematite or goethite) into the fractures and surface of the quartz during or after its initial formation.

Uses & applications

Used primarily by hobbyists for lapidary work (cabochons), as metaphysical 'crystals' (often called 'Fire Quartz' or 'Hematoid Quartz'), and as decorative garden stone or mineral specimens.

Geological facts

The iron staining can sometimes be entirely internal, known as an inclusion, or purely external as a coating. When polished, these specimens are often marketed as 'Harlequin Quartz' if the iron forms distinct red dots or streaks.

Field identification & locations

Identify in the field by its hardness (will scratch glass), glassy luster, and the fact that the orange color often follows internal fracture lines. Found globally in granitic terrains, specifically in Arkansas (USA), Brazil, and Madagascar.

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