mineral

Quartz (Smoky/Grey Variety)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale. Color: Translucent grey to smoky brown. Luster: Vitreous (glass-like). Crystal Structure: Trigonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Translucent grey to smoky brown
Luster: Vitreous (glass-like)

Identified May 15, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale. Color: Translucent grey to smoky brown. Luster: Vitreous (glass-like). Crystal Structure: Trigonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Formation & geological history

Forms in igneous rocks like granite through the cooling of silica-rich magma, or in hydrothermal veins. The color is often the result of natural irradiation and the presence of trace aluminum.

Uses & applications

Used in electronics for its piezoelectric properties, glass manufacturing, as an abrasive, and frequently as a gemstone in jewelry or as a healing crystal in metaphysical practices.

Geological facts

Quartz is one of the most abundant minerals in Earth's continental crust. Smoky quartz was used for early 'sunglasses' in 12th century China to hide the expressions of judges in court.

Field identification & locations

Identify by its ability to scratch glass and lack of cleavage. Look for the characteristic shell-like (conchoidal) fracture pattern. It's found globally in mountainous regions and riverbeds.