mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

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

Hardness: 7 on Mohs scale
Color: Opaque white to translucent
Luster: Vitreous to greasy

Identified April 13, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

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

Formation & geological history

Formed through the crystallization of silica-rich hydrothermal solutions or magma. Milky quartz gets its cloudiness from tiny fluid inclusions of gas or liquid trapped during crystal growth.

Uses & applications

Used in glassmaking, abrasives, silicon production for electronics, and as decorative gravel or landscaping stone. Lower-grade specimens are common for beginner collectors.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is piezo-electric, meaning it generates an electric charge when mechanical pressure is applied, which is why it is used in watches.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife (it will scratch glass instead) and its characteristic lack of cleavage. Look for a greasy feel and glassy sheen on fresh breaks.