mineral

Tumbled smoky quartz

Quartz, silicon dioxide (SiO₂), smoky variety

AI-generated identification · may be incorrect

Typically translucent gray-brown to nearly black with a vitreous luster; Mohs hardness 7, no cleavage, conchoidal fracture, and hexagonal crystal structure. The rounded, polished form indicates human tumbling or shaping.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Smoky quartz forms mainly in silica-rich granite and pegmatite cavities when natural radiation colors otherwise-clear quartz. It commonly occurs in Precambrian to younger granitic rocks, though the specimen’s exact age and locality cannot be determined from the image.

Uses & applications

Used as an ornamental and lapidary stone, in jewelry, carvings, and mineral collections; large clear pieces may have modest gem value.

Geological facts

The smoky color is generally caused by radiation-induced color centers associated with trace aluminum. Dark specimens may be called morion.

Field identification & locations

Look for glassy luster, hardness sufficient to scratch ordinary glass, lack of cleavage, and curved fracture surfaces; confirm with a streak and hardness test rather than appearance alone. Common sources include Brazil, Switzerland, Madagascar, Colorado, and Scotland.