mineral

Quartz (Milky or Smoky)

Silicon Dioxide (SiO2)

Hardness: 7 Mohs; Color: Translucent grey to white; Luster: Vitreous (glassy) to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 Mohs
Color: Translucent grey to white
Luster: Vitreous (glassy) to greasy

Identified May 29, 2026More mineral →

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Physical properties

Hardness: 7 Mohs; Color: Translucent grey to white; Luster: Vitreous (glassy) to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Formation & geological history

Formed primarily through the cooling and crystallization of silica-rich magma or from hydrothermal solutions in veins. It is found in a wide variety of igneous, metamorphic, and sedimentary environments throughout geological time.

Uses & applications

Extensively used in glass manufacturing, electronics (piezoelectric properties), abrasives, construction as an aggregate, and in semi-precious jewelry.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word Quarz, which had its origins in Slavic and West Slavic words meaning 'hard'.

Field identification & locations

Identified in the field by its hardness (scratches glass), lack of cleavage, and glassy appearance on broken surfaces. It is found globally, particularly in mountainous regions and riverbeds.