Rock Identifier
Milky Quartz (Quartz (Silicon Dioxide, SiO2)) — mineral
mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

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

Hardness
7 on Mohs scale
Color
Opaque white
Luster
Vitreous to greasy
Identified More mineral

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Physical properties

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

Formation & geological history

Formed through the crystallization of silica-rich hydrothermal solutions or cooling magma. The milky appearance is caused by tiny inclusions of gas or liquid trapped during crystal growth.

Uses & applications

Used in glassmaking, abrasives, and as a source of silicon for electronics. Lower quality specimens are used for landscaping or as decorative gravel.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz is the most common variety of quartz found in nature.

Field identification & locations

Identify in the field by its ability to scratch glass, its lack of cleavage, and its white, cloudy appearance. It is found globally in pegmatites, hydrothermal veins, and as pebbles in riverbeds.