mineral

Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale; Color: Cloudy white to opaque; Luster: Vitreous to greasy; Crystal structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on the Mohs scale
Color: Cloudy white to opaque
Luster: Vitreous to greasy

Identified March 9, 2026More mineral →

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Physical properties

Hardness: 7 on the Mohs scale; Color: Cloudy white to opaque; 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 silica-rich magma. The cloudy appearance is caused by tiny inclusions of liquid, gas, or both, trapped during crystal growth. Found in various geological ages ranging from Precambrian to Cenozoic.

Uses & applications

Used in the glassmaking industry, as an abrasive, in the production of silicon chips, and as landscape stone or crushed decorative gravel. Low-quality specimens are common for child rock collectors.

Geological facts

Milky Quartz is the most common variety of crystalline quartz. While it lacks the transparency of rock crystal, it can sometimes contain inclusions of gold in specific 'gold-quartz' veins, which are highly prized by miners.

Field identification & locations

Identify in the field by its ability to scratch glass, its lack of cleavage, and its characteristic waxy or milky-white 'ice-like' appearance. It is found globally in igneous, metamorphic, and sedimentary environments, often as veins in granite or as pebbles in riverbeds.