mineral

Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale. Color: White to pale translucent yellow/tan. Luster: Vitreous to greasy. Crystal structure: Hexagonal/Trigonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: White to pale translucent yellow/tan
Luster: Vitreous to greasy

Identified July 21, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins, pegmatites, and igneous intrusion environments where silica-rich fluids cool and crystallize slowly. Tiny gas or liquid bubbles trapped during crystallization give it its milky opacity.

Uses & applications

Used widely as lapidary material, decorative stones, aquariums, landscape ornamentation, and as an ore of silicon for industrial applications.

Geological facts

Milky quartz is one of the most common quartz varieties on Earth. The white or cloudy appearance is caused by microscopic fluid inclusions of gas and liquids trapped during the crystal's growth millions of years ago.

Field identification & locations

Identify by its hardness (scratches glass readily), absence of cleavage, shell-like fracture surfaces, and cloudy white to cream color. Extremely common globally in gravel beds, stream deposits, and pegmatite veins.