mineral

Tumbled smoky quartz (probable)

Quartz, silicon dioxide (SiO₂), smoky variety

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent smoky brown to gray, vitreous luster, and trigonal crystal structure. The rounded shape is mechanically tumbled; internal wispy banding or fractures are visible, with no cleavage and conchoidal fracture.

Identified September 12, 2026More mineral →

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Physical properties

Formation & geological history

Smoky quartz forms in silica-rich igneous, hydrothermal, and pegmatitic environments, commonly acquiring its color from natural irradiation of aluminum-bearing quartz. Individual crystals may be millions to hundreds of millions of years old, depending on the host rock.

Uses & applications

Used as an ornamental and lapidary stone, beads, carvings, and inexpensive jewelry; it has little industrial value compared with ordinary quartz.

Geological facts

Smoky coloration is generally caused by radiation-induced color centers, not by a separate mineral impurity. The image cannot definitively exclude dark tourmaline, obsidian, or another polished stone without testing.

Field identification & locations

Identify by glassy luster, hardness sufficient to scratch ordinary glass, lack of cleavage, and smoky translucency; common sources include Brazil, Switzerland, the United States, Madagascar, and Scotland. A quartz streak is white, while its dark body color does not produce a dark streak.