mineral

Smoky quartz crystal

Quartz (silicon dioxide, SiO₂), likely smoky quartz

AI-generated identification · may be incorrect

Typically translucent brown to nearly black with a vitreous luster, conchoidal fracture, and no cleavage; Mohs hardness 7, hexagonal crystal structure, and specific gravity about 2.65. The specimen appears rough and possibly naturally broken or lightly polished.

Identified September 5, 2026More mineral →

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Physical properties

Formation & geological history

Smoky quartz forms in hydrothermal veins, pegmatites, and cavities of granitic rocks when radiation-induced color centers darken otherwise clear quartz. It occurs in rocks ranging from Precambrian to geologically recent age.

Uses & applications

Used as a decorative and lapidary stone, in jewelry, and as a collector mineral; quartz also has major industrial uses in glass, electronics, and abrasives.

Geological facts

Its smoky color may result from natural irradiation of aluminum-bearing quartz. Very dark material is sometimes marketed as morion.

Field identification & locations

Identify it by its glassy luster, hardness sufficient to scratch ordinary glass, lack of cleavage, and conchoidal fracture; common localities include Brazil, Switzerland, Madagascar, the United States, and Scotland.