Milky Quartz
Silicon Dioxide (SiO2)
Rock Type: mineral

Physical Properties
Hardness: 7 (Mohs scale); Color: White, opaque to translucent; Luster: Vitreous to waxy when polished; Crystal Structure: Hexagonal (Trigonal); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.65
Formation & Geological History
Formed through the crystallization of silica-rich hydrothermal fluids in veins or as a late-stage mineral in igneous pegmatites. The white color is caused by minute fluid inclusions of gas or liquid trapped during crystal growth.
Uses & Applications
Used in glassmaking, as an abrasive, in electronics (piezoelectric properties), and frequently as decorative garden stones, tumbled pocket stones, or in costume jewelry.
Geological Facts
Milky quartz is the most common variety of crystalline quartz. It is often found in large veins that can be hundreds of feet long, frequently hosting gold in hydrothermal deposits.
Field Identification & Locations
Identify in the field by its hardness (scratches glass), lack of cleavage, and typical white, 'cloudy' appearance. It is found globally, particularly in mountainous regions and riverbeds as rounded pebbles.
Identified on: 5/13/2026
Mode: Standard