mineral

Smoky quartz (likely)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Translucent gray-brown, vitreous luster, conchoidal fracture, and no obvious cleavage; Mohs hardness 7, hexagonal crystal structure, specific gravity about 2.65. The rough, irregular piece may also contain surface iron-oxide staining or inclusions.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids or granitic pegmatites crystallize, with natural irradiation producing the smoky color; commonly Precambrian to Cenozoic in age depending on locality. Typical sources include Brazil, the United States, Switzerland, Madagascar, and Spain.

Uses & applications

Used as a collector specimen, ornamental stone, and occasionally in carvings and jewelry; industrial quartz is important in glass, electronics, and abrasives, though this specimen is unlikely to have industrial value.

Geological facts

Smoky quartz is colored by radiation-induced defects in the crystal lattice, not usually by a separate pigment. Very dark varieties are called morion.

Field identification & locations

Identify by its glassy luster, hardness sufficient to scratch ordinary glass, conchoidal fracture, and lack of cleavage; avoid confusing it with glass, which is generally softer or contains bubbles. Common rough specimens typically sell for $5–$30; unusually clear, well-formed crystals may bring $50–$200+.