mineral

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

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

Hardness: 7 on Mohs scale
Luster: Vitreous (glassy) to greasy

Identified March 31, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the crystallization of silica-rich hydrothermal fluids in veins or as a primary constituent of igneous pegmatites. The yellowish staining is due to secondary weathering and the infiltration of iron-bearing groundwater.

Uses & applications

Used in glass manufacturing, electronics (due to piezoelectric properties), abrasives, and as a common landscaping stone or gravel. Low-grade specimens like this are primarily for amateur collecting.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. The 'milky' appearance is caused by tiny inclusions of gas or liquid trapped during the crystal's growth over millions of years.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife (it will scratch glass), its lack of cleavage planes, and its characteristic waxy/glassy look. Extremely common globally in almost all geological environments.

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