mineral

Smoky quartz crystal

Quartz, silicon dioxide (SiO₂), likely natural prismatic crystal

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent smoky brown-gray color, vitreous luster, hexagonal/trigonal crystal structure, and indistinct cleavage with conchoidal fracture. The specimen appears internally fractured and partially included, with a terminated prismatic form.

Identified August 28, 2026More mineral →

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Physical properties

Formation & geological history

Forms in silica-rich hydrothermal veins, pegmatites, and cavities in igneous rocks; smoky coloration commonly results from natural irradiation affecting aluminum impurities. Individual crystals may form over thousands to millions of years.

Uses & applications

Used as a collector specimen, ornamental stone, and occasionally in jewelry; quartz is also important industrially in glass, electronics, and precision oscillators.

Geological facts

Smoky quartz is the national gemstone of Scotland and is often called cairngorm when especially attractive. Its color can sometimes be produced or intensified by irradiation.

Field identification & locations

Identify by its glassy luster, hexagonal prism, hardness sufficient to scratch ordinary glass, and lack of metallic or pearly cleavage. Common sources include Brazil, Switzerland, the United States, Madagascar, and the Alps.