mineral

Smoky quartz crystal

Quartz, silicon dioxide (SiO₂), likely smoky variety

AI-generated identification · may be incorrect

Translucent gray-brown to nearly black, with vitreous luster and conchoidal fracture; Mohs hardness 7, hexagonal crystal structure, no true cleavage, and specific gravity about 2.65. The specimen appears raw and fractured, with possible iron- or radiation-induced smoky coloration.

Identified September 5, 2026More mineral →

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Physical properties

Formation & geological history

Forms in silica-rich hydrothermal veins, pegmatites, and cavities in igneous rocks; smoky color develops through natural irradiation of aluminum-bearing quartz. Individual crystals range from recent growth to hundreds of millions of years old, depending on the host deposit.

Uses & applications

Used as a collectible mineral and occasionally as a gemstone when transparent and well-formed; quartz is also essential in glass, electronics, abrasives, and engineered stone.

Geological facts

Smoky quartz can grade from pale gray (“cairngorm”) to opaque morion. Its color may fade with strong heating or prolonged sunlight, and some commercial dark material is artificially irradiated.

Field identification & locations

Identify it by hardness, glassy luster, conchoidal fracture, and lack of cleavage; it should scratch ordinary glass but not be scratched by a steel knife. Common sources include Brazil, Switzerland, Scotland, Colorado, Arkansas, and Madagascar.