mineral
Smoky quartz-bearing rock
Smoky quartz (SiO₂), possibly in a pegmatitic or quartz-rich matrix
AI-generated identification · may be incorrectTranslucent brown-to-gray material with vitreous luster and irregular fracture; quartz hardness is Mohs 7, with no cleavage and specific gravity about 2.65. The granular, dark matrix suggests an included or matrix-bearing quartz specimen rather than a clean crystal.
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Physical properties
Translucent brown-to-gray material with vitreous luster and irregular fracture; quartz hardness is Mohs 7, with no cleavage and specific gravity about 2.65. The granular, dark matrix suggests an included or matrix-bearing quartz specimen rather than a clean crystal.
Formation & geological history
Smoky color forms when natural irradiation activates aluminum impurities in quartz, commonly in granites and pegmatites; the specimen’s exact age and locality cannot be determined from the image. Associated dark material may be mica, iron oxides, or other matrix minerals.
Uses & applications
Common smoky quartz is used as a decorative and lapidary stone, in cabochons and crystal collections; quartz also has major industrial uses in glass, ceramics, electronics, and abrasives.
Geological facts
Smoky quartz ranges from pale champagne to nearly black morion; heating can remove the smoky color, while irradiation can produce it artificially.
Field identification & locations
Identify by its glassy luster, lack of cleavage, conchoidal fracture, and scratch resistance; a steel file should not scratch it. Common localities include Brazil, Switzerland, the United States, Madagascar, and Scotland.
