mineral

Ferruginous Quartz

Silicon Dioxide with Hematite/Limonite inclusions (SiO2 + Fe2O3)

Hardness: 7 on Mohs scale; Color: Reddish-brown, orange, brownish-tan; Luster: Vitreous to waxy (when polished); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Reddish-brown, orange, brownish-tan
Luster: Vitreous to waxy (when polished)

Identified May 9, 2026More mineral →

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Physical properties

Formation & geological history

Formed through hydrothermal processes where iron oxides (hematite or limonite) are included during or after the quartz crystal growth. Common in sedimentary iron formations and as secondary minerals in volcanic cavities.

Uses & applications

Used primarily as a decorative stone, in lapidary work for cabochons or tumbled stones, and as a collector's specimen. In some cultures, it is used as a healing stone (Healer's Gold or Hematoid Quartz).

Geological facts

The red color is caused by microscopic particles of hematite. It is often referred to as 'Hematoid Quartz' or 'Fire Quartz' in the gemstone trade. Its color can range from a light yellow to a deep, dark red depending on the iron concentration.

Field identification & locations

Identify in the field by its hardness (scratches glass), lack of cleavage, and the characteristic rusty-red staining within the translucent quartz body. Commonly found in iron-rich geological regions like the Lake Superior area and parts of Brazil.

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