mineral

Smoky quartz crystal

Quartz, silicon dioxide (SiO₂), brown variety colored by irradiation-related defects

AI-generated identification · may be incorrect

Typically Mohs hardness 7, vitreous luster, transparent to translucent brown-gray color, and a hexagonal crystal structure with conchoidal fracture and no cleavage. The specimen appears to be a small rough, partly terminated crystal, though the image is not sufficient for certainty.

Identified September 7, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins, cavities in igneous rocks, and pegmatites as silica-rich fluids cool; crystals range from ancient Precambrian specimens to geologically recent deposits. Brown color commonly develops through natural radiation acting on trace aluminum impurities.

Uses & applications

Used as a decorative and collectible mineral, occasionally in jewelry; quartz is also essential in glass, electronics, abrasives, and engineered stone.

Geological facts

Smoky quartz can fade with strong heat or sunlight, while very dark varieties may approach morion. It is distinguished from dark glass by its crystal faces, hardness, and lack of bubbles.

Field identification & locations

Common localities include Brazil, Switzerland, the United States, Madagascar, and Scotland; inspect for hexagonal prisms, pyramidal terminations, and uniform internal color. A small ordinary specimen is typically worth $5-$25; well-formed, transparent crystals may sell for $50-$500+.