Mineral

Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White to semi-translucent; Luster: Vitreous to greasy; Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: White to semi-translucent
Luster: Vitreous to greasy

Identified March 24, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: White to semi-translucent; Luster: Vitreous to greasy; Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. The white 'milky' appearance is caused by tiny fluid inclusions of gas and liquid trapped during crystal growth. They are found across all geological ages.

Uses & applications

Used in glassmaking, as an abrasive, in the production of silicon metal for electronics (though usually higher purity quartz is preferred), and widely used in landscaping or as a gemstone in inexpensive jewelry.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz is the most common variety of quartz. Some milky quartz contains traces of gold within its hydrothermal veins, making it a primary target for gold prospectors.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), lack of cleavage (it breaks in curved, shell-like patterns), and its characteristic white 'opaque' color. It is commonly found in gravel pits, mountain streams, and within granite outcrops worldwide.