mineral

Tumbled smoky quartz (probable)

Quartz, SiO₂; smoky variety colored by irradiation-related defects

AI-generated identification · may be incorrect

Translucent gray-brown to nearly black, vitreous luster, generally massive in this polished form, with no obvious cleavage and conchoidal fracture. Mohs hardness 7; specific gravity about 2.65.

Identified August 23, 2026More mineral →

Explore Tumbled smoky quartz (probable) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Translucent gray-brown to nearly black, vitreous luster, generally massive in this polished form, with no obvious cleavage and conchoidal fracture. Mohs hardness 7; specific gravity about 2.65.

Formation & geological history

Forms in silica-rich hydrothermal veins, pegmatites, and cavities in igneous and metamorphic rocks; coloration develops from natural or artificial irradiation of aluminum-bearing quartz. Quartz ranges from Precambrian to modern geological ages.

Uses & applications

Used as a decorative and collecting stone, in jewelry, carvings, and polished specimens; quartz also has major industrial uses in glass, electronics, abrasives, and engineered stone.

Geological facts

The rounded, glossy surface indicates tumbling or polishing, which obscures natural crystal faces and makes exact identification less certain from the image alone.

Field identification & locations

Common sources include Brazil, Madagascar, the United States, Switzerland, and Scotland. Confirm with hardness testing—quartz scratches ordinary glass but should not be scratched by a steel knife—and inspect for glassy fracture and internal veils.