mineral

Milky Quartz

Silicon Dioxide (SiO2)

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

Hardness: 7 Mohs scale
Color: Milky white to light tan/yellow
Luster: Vitreous to greasy

Identified May 1, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed in hydrothermal veins or pegmatites where silica-rich fluids cooled slowly. Often found as water-worn river pebbles or in glacial till. The milky appearance is caused by tiny inclusions of gas or liquid trapped during crystal growth.

Uses & applications

Used in construction as decorative aggregate, in the glass-making industry, as an abrasive, and frequently by lapidarists for tumbling and rock collecting.

Geological facts

Quartz is the second most abundant mineral in the Earth's continental crust. Milky quartz is the most common variety of crystalline quartz found in nature. Historic gold miners often used milky quartz as an indicator for looking for gold veins.

Field identification & locations

Identified by its waxy-to-glassy luster, inability to be scratched by a steel knife, and irregular, rounded edges if found near water. Common globally in riverbeds and mountainous terrain.