mineral

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide inclusions

AI-generated identification · may be incorrect

Hardness: 7 (Mohs scale), Color: White to translucent with yellow-brown staining, Luster: Vitreous to greasy, Crystal structure: Hexagonal, Cleavage: None (conchoidal fracture)

Identified July 19, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: White to translucent with yellow-brown staining, Luster: Vitreous to greasy, Crystal structure: Hexagonal, Cleavage: None (conchoidal fracture)

Formation & geological history

Formed in hydrothermal veins and pegmatites. The yellow-brown coloration is caused by the secondary infiltration of iron oxides like limonite or goethite into fractures or surfaces of the quartz.

Uses & applications

Informal collecting, lapidary use for tumbles, and sometimes crushed for industrial silica extraction.

Geological facts

Iron-stained quartz is one of the most common rock-forming minerals found on Earth's surface. The 'golden' or rusty hue is purely a surface or crack-filling impurity rather than a chemical change to the quartz crystal lattice itself.

Field identification & locations

Identify by its ability to scratch glass (hardness 7) and its lack of cleavage. It is found globally in almost any environment where quartz veins weather out of bedrock. Look for it in stream beds or rocky outcrops.