mineral

Smoky quartz crystal fragment

Quartz (silicon dioxide, SiO₂), likely smoky variety

AI-generated identification · may be incorrect

Transparent to translucent brown-gray with a vitreous luster and irregular, partly conchoidal fracture; quartz has Mohs hardness 7, trigonal crystal structure, and no cleavage. The photo does not show enough detail to confirm the smoky variety.

Identified October 5, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich fluids in veins, pegmatites, and cavities; smoky coloration commonly develops through natural irradiation of trace aluminum-bearing quartz. Its age depends on the host deposit and cannot be determined from the image.

Uses & applications

Used in jewelry and decorative pieces; quartz is also important in glassmaking, electronics, and industrial abrasives.

Geological facts

Quartz is among Earth’s most abundant minerals; smoky coloration is typically caused by irradiation-related color centers.

Field identification & locations

Look for glassy luster, hardness sufficient to scratch ordinary glass, and lack of cleavage; common worldwide, especially in granites and hydrothermal veins. A small rough fragment like this is typically worth about $1–$10 USD.