mineral

Milky quartz

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness 7 Mohs; white to translucent with a glassy-to-waxy luster and irregular fracture. It has a hexagonal crystal structure, but this specimen shows no obvious crystal faces or cleavage.

Identified September 28, 2026More mineral →

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Physical properties

Hardness 7 Mohs; white to translucent with a glassy-to-waxy luster and irregular fracture. It has a hexagonal crystal structure, but this specimen shows no obvious crystal faces or cleavage.

Formation & geological history

Forms when silica-rich fluids crystallize in veins and cavities, or during cooling of silica-rich magma. Quartz is common across many geological ages and settings.

Uses & applications

Used as a decorative and lapidary stone, and quartz is an important industrial source of silica for glass and electronics.

Geological facts

Its cloudy appearance comes from microscopic fluid or gas inclusions and other imperfections within the quartz.

Field identification & locations

Common worldwide in quartz veins, pegmatites, and stream gravels; look for glassy surfaces, hardness sufficient to scratch glass, and lack of cleavage. The pictured rounded piece may be naturally water-worn.