mineral

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

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

Hardness: 7 on Mohs scale
Color: White to opaque (milky)
Luster: Vitreous to greasy

Identified March 22, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: White to opaque (milky); 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 tiny fluid inclusions of gas or liquid trapped during crystal growth. They can be found in rocks from nearly all geological ages.

Uses & applications

Used in the production of glass, ceramics, and abrasives. In construction, it is used as a component in concrete and mortar. High-quality specimens are used in jewelry and electronics (piezoelectric applications).

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Historically, it was used by many ancient cultures for stone tools and ritual objects. It is the only mineral that consists entirely of silicon and oxygen.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife and its lack of cleavage (it breaks in irregular, shell-like curves). Commonly found in quartz veins, pegmatites, and as a major component of granite.