mineral

Quartz (Smoky/Milky variety)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Translucent grey to milky white; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Translucent grey to milky white
Luster: Vitreous (glassy)

Identified March 25, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Translucent grey to milky white; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed through the crystallization of magma or from hydrothermal veins. It is found in all geological ages and environments, particularly in igneous rocks like granite and metamorphic rocks like quartzite.

Uses & applications

Used widely in glassmaking, electronics (piezoelectric properties), abrasives, and as a semi-precious gemstone in jewelry and decorative carvings.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German 'Quarz' and Greek 'krustallos', meaning 'ice'. It is resistant to both chemical and physical weathering.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife (H=7) and its lack of cleavage. Found globally; major deposits in Brazil, USA (Arkansas), and the Alps. Collectors look for clarity and well-defined crystal faces.

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