mineral

Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to opaque; Luster: Vitreous to greasy; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

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

Identified May 27, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Milky 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 cooling of magma or hydrothermal activity. The milky appearance is caused by tiny inclusions of gas or liquid trapped during crystal growth. They are found in igneous, metamorphic, and sedimentary environments across all geological eras.

Uses & applications

Used in glassmaking, abrasives, electronics (piezoelectric properties), and as a gemstone for jewelry or interior decoration. Large specimens are popular with collectors.

Geological facts

Quartz is one of the most abundant minerals in Earth's crust. Milky quartz is the most common variety of crystalline quartz. Historically, it was used to produce stone tools in many ancient cultures.

Field identification & locations

Identify in the field by its hardness (it can scratch glass), its white color, and its lack of cleavage. Often found in hydrothermal veins. Common locations include Brazil, USA (Arkansas/South Dakota), and the Alps.