mineral

Ferruginous Quartz

Silicon Dioxide (SiO2) with iron oxide inclusions (Limonite/Goethite)

Hardness: 7 (Mohs scale); Color: Yellow-brown, tan, to orange; Luster: Vitreous to waxy; Structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Hardness: 7 (Mohs scale)
Color: Yellow-brown, tan, to orange
Luster: Vitreous to waxy

Identified April 7, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Yellow-brown, tan, to orange; Luster: Vitreous to waxy; Structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Formation & geological history

Formed in hydrothermal veins or as a secondary mineral where silicon-rich waters crystallize. The yellow-brown staining is caused by the oxidation of iron-bearing minerals that seep into the quartz structure.

Uses & applications

Used primarily by mineral collectors, as decorative pocket stones, and sometimes in metaphysical practices. In large industrial scales, quartz is used in glass making and electronics.

Geological facts

Also known as 'Iron Quartz' or 'Limonitic Quartz.' The yellow-brown coating is often just on the surface or in microscopic fractures, acting as a natural pigment for the crystal.

Field identification & locations

Identify in the field by its high hardness (it will scratch glass), lack of cleavage, and the characteristic rusty-yellow staining. Commonly found in riverbeds, mountain scree, and mining tailings.

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