Milky Quartz

Physical Properties

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

Formation & Geological History

Formed from silica-rich hydrothermal fluids cooling in veins/pockets, or as a constituent in igneous and metamorphic rocks. The white color comes from tiny fluid inclusions trapped during crystal growth.

Uses & Applications

Used in glassmaking, electronics (piezoelectric properties), jewelry (cabochons), and as landscaping/ground cover.

Geological Facts

Milky quartz is the most common variety of crystalline quartz. It can often be found associated with gold in hydrothermal vein deposits, leading prospectors to call it 'bull quartz'.

Field Identification & Locations

Identify by its hardness (it will scratch glass), its white 'milky' appearance, and its lack of cleavage. Often found in riverbeds or as rounded 'cobbles' due to erosion.

Identified on: 4/27/2026

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