mineral

Smoky quartz in matrix

Quartz, silicon dioxide (SiO₂), smoky variety

AI-generated identification · may be incorrect

Translucent gray-brown, vitreous luster, conchoidal fracture, no visible cleavage, Mohs hardness 7, and specific gravity about 2.65. The darker crystal is embedded in a coarse, likely feldspar- and mica-bearing granitic matrix.

Identified September 4, 2026More mineral →

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Physical properties

Formation & geological history

Smoky quartz forms when natural radiation creates color centers in quartz within granite, pegmatites, or hydrothermal veins; its age depends on the host rock, commonly Paleozoic to Precambrian. The specimen appears naturally attached to weathered matrix, with possible human trimming or polishing.

Uses & applications

Used as a collector specimen and occasionally as a gemstone; quartz is important industrially in glass, electronics, abrasives, and ceramics. Matrix specimens generally have modest decorative rather than commercial value.

Geological facts

Smoky coloration ranges from pale gray to nearly black and may fade with heating or intense light. Quartz is one of Earth’s most abundant and chemically durable minerals.

Field identification & locations

Identify it by hardness, glassy luster, translucent smoky color, and conchoidal fracture; it should scratch glass but not be scratched by a steel knife. Common sources include Brazil, Switzerland, the United States, Madagascar, and Scotland.