mineral

Quartz (Iron-Stained)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: Dirty yellow-brown (due to iron oxide staining), Luster: Vitreous to greasy, Crystal Structure: Hexagonal (trigonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified May 3, 2026More mineral →

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Physical properties

Formation & geological history

Formed through hydrothermal processes or within igneous pegmatites. The yellow/brown color is a surface secondary coating of limonite or goethite (iron oxides) deposited by groundwater or weathering.

Uses & applications

Primarily used in construction (aggragate), glass manufacturing, and electronics when pure. Stained specimens are often collected by hobbyists or tumble-polished.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is colorless, but impurities and surface staining can create a rainbow of variations.

Field identification & locations

Identify in the field by its hardness (it will easily scratch glass) and its lack of cleavage. Found globally in almost all geological environments, particularly streambeds and veins in bedrock.