Rock Identifier
Smoky quartz-bearing rock (Smoky quartz (SiO₂), possibly in a pegmatitic or quartz-rich matrix) — mineral
mineral

Smoky quartz-bearing rock

Smoky quartz (SiO₂), possibly in a pegmatitic or quartz-rich matrix

AI-generated identification · may be incorrect

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.

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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.