mineral

Ferruginous Quartz (Iron-stained Quartz)

Silicon Dioxide (SiO2) with Hematite/Goethite inclusions

Hardness: 7 (Mohs scale); Color: Tan, orange-brown, or rusty yellow due to iron oxide staining; Luster: Vitreous (glassy) to dull when weathered; Crystal Structure: Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 (Mohs scale)
Luster: Vitreous (glassy) to dull when weathered

Identified March 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or as a secondary mineral in sedimentary environments. The iron staining occurs when groundwater rich in iron oxides percolates through the quartz or when iron minerals oxidize on the surface. These specimens can range in age from millions to billions of years old.

Uses & applications

Primarily used as decorative landscaping stone, drainage gravel, or as a beginner's specimen for hobbyist collectors. High-purity quartz is used in glassmaking and electronics, but iron-stained varieties are typically discarded for industrial use.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Ferruginous quartz specifically is often mistaken for gold or amber by novice collectors due to its warm, glassy yellow-orange appearance when wet or polished.

Field identification & locations

Identify in the field by its hardness (it will easily scratch glass) and lack of cleavage. Look for the translucent interior beneath the rusty exterior coating. These are commonly found in riverbeds, glacial tills, and near weathered granite outcrops globally.

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