mineral

Smoky Quartz

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 (Mohs scale); Color: Brownish-grey to black; Luster: Vitreous; Crystal system: Trigonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Brownish-grey to black
Luster: Vitreous

Identified July 18, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Brownish-grey to black; Luster: Vitreous; Crystal system: Trigonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Forms through the natural irradiation of aluminum-bearing quartz in granitic pegmatites or hydrothermal veins. Often found in pockets within igneous rocks.

Uses & applications

Used extensively in jewelry, ornamental carvings, and as a popular specimen for crystal healing and mineral collecting.

Geological facts

The dark color is caused by free silicon formed from silicon dioxide by natural irradiation. If heated to about 300-400 degrees Celsius, it will lose its color.

Field identification & locations

Identify by its transparency combined with charcoal or tea-like smoky hues. Found globally, with notable deposits in the Swiss Alps, Brazil, and the United States (Colorado).