Milky Quartz

Physical Properties

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

Formation & Geological History

Formed through the cooling of silica-rich hydrothermal fluids in veins or as a constituent in igneous rocks like granite. The white 'milky' color is caused by microscopic fluid inclusions of gas or liquid trapped during crystal growth.

Uses & Applications

Used in glassmaking, abrasives, electronics (due to piezoelectric properties), and as decorative landscaping stone or semi-precious gemstones in jewelry.

Geological Facts

Milky quartz is the most common variety of crystalline quartz. While often found as massive lumps, it can form large, well-defined prismatic crystals in cavities or pockets.

Field Identification & Locations

Identify in the field by its ability to scratch glass, its lack of cleavage, and its characteristic 'waxy' or 'fatty' luster on fresh surfaces. It is ubiquitous in mountainous regions and riverbeds.

Identified on: 4/15/2026

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