Milky Quartz

Physical Properties

Mohs hardness: 7. Color: White to cloudy. Luster: Vitreous to greasy. Crystal structure: Trigonal (hexagonal). Cleavage: Indistinct/None (Conchoidal fracture). Specific Gravity: 2.65.

Formation & Geological History

Formed in hydrothermal veins and pegmatites during the cooling of silica-rich magma. The milky appearance is caused by tiny fluid inclusions of gas or liquid trapped during crystal growth.

Uses & Applications

Used in glass making, abrasives, and as a source of silicon for electronics. Lower grade milky specimens are often used in landscaping or as decorative stones for beginner collectors.

Geological Facts

Milky quartz is the most common variety of crystalline quartz. It is often found associated with gold-bearing veins, making it a key indicator mineral for gold prospectors throughout history.

Field Identification & Locations

Identify in the field by its hardness (it will scratch glass and steel), its white opaque color, and its lack of cleavage planes. Found globally in almost all geological environments.

Identified on: 5/16/2026

Mode: Standard