mineral

Milky Quartz with Iron Oxide

Quartz (Silicon Dioxide, SiO2) with Limonite/Goethite staining

Hardness: 7 (Mohs scale); Color: White to translucent with orange/brown staining; Luster: Vitreous to greasy; Crystal Structure: Hexagonal (Trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: White to translucent with orange/brown staining
Luster: Vitreous to greasy

Identified June 12, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or pegmatites as silicon dioxide precipitates from hot aqueous solutions. The reddish-orange staining is caused by secondary oxidation of iron-bearing minerals (like pyrite) into limonite or goethite.

Uses & applications

Quartz is used in glassmaking, electronics (piezoelectric properties), and as an abrasive. Stained specimens are primarily for basic mineral collecting or landscaping.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Ferruginous quartz, like this one, is often found in 'gossans' or iron caps above ore deposits.

Field identification & locations

Identify by its ability to scratch glass, its lack of cleavage, and its waxy/glassy appearance under the iron staining. Found globally in riverbeds, mountains, and mining tailings.

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