mineral

Quartz (Smoky/Milky Variety)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

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

Hardness: 7 on Mohs scale
Color: Gray, brown, to white
Luster: Vitreous to greasy

Identified July 1, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Gray, brown, to 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 magma or from hydrothermal veins. Smoky varieties often gain color from natural irradiation of aluminum impurities over millions of years.

Uses & applications

Used in glass manufacturing, electronics (piezoelectric properties), abrasives, and as semi-precious gemstones in jewelry and decor.

Geological facts

Quartz is one of the most abundant minerals in Earth's crust. Smoky quartz is the national gem of Scotland, where it is known as Cairngorm.

Field identification & locations

Identify by its hardness (scratches glass), lack of cleavage, and waxy-to-glassy luster. Commonly found in granitic pegmatites and metamorphic rocks wordwide.