mineral

Smoky Quartz

Silicon Dioxide (SiO2)

Hardness: 7; Color: Translucent yellowish-brown to grayish-black; Luster: Vitreous; Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7
Color: Translucent yellowish-brown to grayish-black
Luster: Vitreous

Identified June 18, 2026More mineral →

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Physical properties

Hardness: 7; Color: Translucent yellowish-brown to grayish-black; Luster: Vitreous; Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Forms in igneous rocks like pegmatites and metamorphic rocks through hydrothermal processes. The color is caused by natural irradiation of trace aluminum impurities.

Uses & applications

Used in gemstone jewelry, ornamental carvings, as a healing crystal in metaphysical circles, and historically in early sunglasses and optical instruments.

Geological facts

The smoke-like color is the result of free silicon formed from silicon dioxide by natural irradiation. It is the national gem of Scotland and has been used in jewelry there for centuries.

Field identification & locations

Identify by its translucent brownish hue and ability to scratch glass (Hardness 7). Commonly found in the Swiss Alps, Brazil, and Pikes Peak, Colorado. Look for it in granite cavities.