mineral

Smoky quartz

Quartz (SiO₂), brown-to-gray smoky variety

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent gray-brown color, vitreous luster, conchoidal fracture, no cleavage, hexagonal crystal structure, and specific gravity about 2.65. The rough, massive specimen appears partly cloudy and iron-stained, with possible minor feldspar or mica inclusions.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Forms mainly in granitic pegmatites, hydrothermal veins, and cavities when natural radiation creates color centers in quartz; individual crystals may range from ancient Precambrian to recent geological ages. Exact age and locality cannot be determined from the image alone.

Uses & applications

Used as a decorative and lapidary stone, in jewelry, carvings, and mineral collections; quartz is also important industrially in glass, electronics, and abrasives.

Geological facts

Smoky coloration can fade with prolonged heating or intense sunlight, while some commercial smoky quartz is artificially irradiated. The specimen’s irregular massive form is more typical of vein or pegmatite material than a complete crystal.

Field identification & locations

Identify by its glassy luster, hardness, conchoidal fracture, and inability to scratch with a steel knife; it should scratch ordinary glass. Common sources include Brazil, Switzerland, Scotland, Madagascar, and the United States, especially Colorado and New Hampshire.