Milky Quartz with Iron Staining

Physical Properties

Hardness: 7 on Mohs scale; Color: Milky white with reddish-brown (iron) staining; Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & Geological History

Formed from silica-rich hydrothermal solutions or cooling magma in igneous veins and metamorphic rocks. Can be found in geological formations of almost any age, from Precambrian to Cenozoic.

Uses & Applications

Industrial uses include glass making, abrasives, and electronics (as a source of silicon). In jewelry, it is used for beads or cabochons. Collectors value unique iron-stained patterns.

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 crystal growth. Iron staining is usually a secondary environmental coating caused by hematite or goethite.

Field Identification & Locations

Identify in the field by its ability to scratch glass and lack of cleavage. Often found as surface float, in stream beds, or within exposed quartz veins. Look for a waxy or glassy luster on fresh surfaces.

Identified on: 4/21/2026

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