Milky Quartz
Silicon Dioxide (SiO2)
Rock Type: mineral

Physical Properties
Hardness: 7 on Mohs scale; Color: Cloudy white to opaque; 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 magma or from hydrothermal veins where hot water deposits silicon and oxygen into cracks. Found globally in all geological environments.
Uses & Applications
Used in glassmaking, abrasives, electronic oscillators (piezoelectric properties), jewelry, and as a decorative stone in landscaping.
Geological Facts
Milky quartz gets its characteristic white cloudiness from tiny inclusions of gas or liquid trapped during the crystal's formation over millions of years.
Field Identification & Locations
Identify by its hardness (scratches glass), lack of cleavage, and white color. Very common in igneous terrain and stream beds. Common in North America, Brazil, and Madagascar.
Identified on: 5/3/2026
Mode: Standard