mineral

Smoky quartz crystal fragment

Quartz (SiO₂), smoky variety

AI-generated identification · may be incorrect

Dark brown to gray, translucent, and glassy; Mohs hardness 7, trigonal crystal structure, and no cleavage (fractures unevenly). The specimen appears to be a small, naturally broken crystal fragment.

Identified October 4, 2026More mineral →

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Physical properties

Dark brown to gray, translucent, and glassy; Mohs hardness 7, trigonal crystal structure, and no cleavage (fractures unevenly). The specimen appears to be a small, naturally broken crystal fragment.

Formation & geological history

Forms when silica-rich fluids crystallize in cavities and pegmatites; smoky coloration comes from radiation-induced defects in the crystal. Quartz occurs in rocks of many ages, so the specimen’s age cannot be determined from the image.

Uses & applications

Quartz is used in glass, electronics, and abrasives; attractive smoky quartz is cut for jewelry and collected as crystals.

Geological facts

Smoky quartz’s color can fade with prolonged exposure to sunlight or heat.

Field identification & locations

Look for glassy luster, hardness sufficient to scratch glass, and lack of cleavage; common sources include Brazil, Madagascar, and the Alps. A small, broken fragment like this is typically worth about $1–$10.