mineral
Ferruginous Quartz
Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions
Hardness: 7 on Mohs scale; Color: Rusty brown, orange, and white; Luster: Vitreous to dull; Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- Rusty brown, orange, and white
- Luster
- Vitreous to dull
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Physical properties
Hardness: 7 on Mohs scale; Color: Rusty brown, orange, and white; 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 mineral where silica-rich fluids permeate through rock and become stained by iron oxides like hematite or limonite. Found in various geological ages.
Uses & applications
Used primarily in lapidary work for cabochons or beads, decorative landscaping, and as a collector's specimen. In industry, pure quartz is used for glass and electronics.
Geological facts
Also known as Eisenkiesel or Iron Quartz. The reddish-brown color is not part of the quartz crystal lattice itself but is caused by microscopic particles of iron trapped within or coating the crystal surfaces.
Field identification & locations
Identify in the field by its hardness (ability to scratch glass), lack of cleavage, and characteristic orange-brown 'rust' staining. Commonly found in riverbeds, tailings piles, and quartz veins.
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