mineral

Milky Quartz

Silicon Dioxide (SiO2)

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

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

Identified March 25, 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; Cleavage: None (Conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. The milky appearance is caused by microscopic inclusions of fluids (gas or liquid) trapped during crystal growth. They can be found in rocks from virtually any geological era.

Uses & applications

Used as a gemstone (tumbled or cabochon), in glassmaking, as a source of silicon for electronics, and widely used in concrete and as a landscaping decorative stone.

Geological facts

Milky Quartz is the most common variety of crystalline quartz. While it lacks the transparency of rock crystal, it is the parent material for many other quartz varieties and is often found in the core of pegmatites.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), its cloudy white appearance, and lack of cleavage. It is commonly found in gravel pits, riverbeds, and as veins in metamorphic and igneous outcroppings worldwide.