mineral

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Translucent white to milky with rusty orange/brown iron oxide staining; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Luster: Vitreous to waxy

Identified June 10, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or pegmatites when silica-rich fluids cool. The iron staining occurs when the specimen is exposed to groundwater containing iron oxides like hematite or goethite, which seep into fractures or coat the surface.

Uses & applications

Quartz is used in glassmaking, electronics (piezoelectric properties), and as an abrasive. Stained specimens are primarily for amateur collecting or as indicators for gold prospecting in quartz veins.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Iron-stained quartz is often called 'rusty quartz' by prospectors because it can indicate the presence of sulfide minerals which sometimes carry gold.

Field identification & locations

Identify by its hardness (it will scratch glass), its lack of cleavage, and the characteristic rusty coating that doesn't wash off easily. Found globally in almost all geological environments.

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