mineral

Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: White to translucent gray, Luster: Vitreous to greasy, Crystal Structure: Hexagonal (trigonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified April 22, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: White to translucent gray, Luster: Vitreous to greasy, Crystal Structure: Hexagonal (trigonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & geological history

Formed from the crystallization of silica-rich hydrothermal fluids in veins or as a late-stage mineral in igneous pegmatites. It can be found in rocks of all ages, from Precambrian to Cenozoic.

Uses & applications

Used as a source of silicon for electronics, an abrasive in sandblasting, a flux in smelting, and in glassmaking. Common in landscaping and as a decorative collector specimen.

Geological facts

The white 'milky' color is caused by millions of tiny fluid inclusions of gas and/or liquid trapped during the crystal's growth. It is the most common variety of crystalline quartz.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), its lack of cleavage, and its characteristic waxy or glassy luster. It is found globally, often as white veins cutting through darker rock.