mineral

Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White to translucent cloudy; Luster: Vitreous to greasy; Crystal Structure: Trigonal (hexagonal prisms); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

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

Identified April 13, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: White to translucent cloudy; Luster: Vitreous to greasy; Crystal Structure: Trigonal (hexagonal prisms); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed through the crystallization of silica-rich hydrothermal solutions or cooling magma. Milky quartz gets its characteristic white color from microscopic inclusions of gas or liquid trapped during crystal growth. It is found in igneous, metamorphic, and sedimentary environments across all geological ages.

Uses & applications

Used as a source of silica for glassmaking, as an abrasive, in the production of silicon wafers for electronics, as landscaping stone, and occasionally in jewelry as cabochons or decorative carvings.

Geological facts

Milky quartz is the most common variety of crystalline quartz. While most 'crystals' are clear, the white opacity of milky quartz is caused by tiny bubbles of gas and liquid that reflect light.

Field identification & locations

Identify in the field by its hardness (will scratch glass/steel), lack of cleavage, and characteristic waxy-to-glassy luster. It is ubiquitous globally, often found in quartz veins or as river-worn pebbles. For collectors, look for large, well-formed terminal faces.