mineral

Tumbled smoky quartz (probable)

Quartz, silicon dioxide (SiO₂), smoky variety

AI-generated identification · may be incorrect

Translucent brown-gray to nearly black, vitreous luster, conchoidal fracture, no cleavage, Mohs hardness 7, and specific gravity about 2.65. The rounded edges indicate mechanical tumbling and polishing; internal fractures and inclusions are visible.

Identified August 25, 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

Formation & geological history

Smoky quartz forms when natural radiation or aluminum impurities color quartz in hydrothermal veins, pegmatites, and granitic rocks; individual crystals may range from recent to Precambrian in age. The specimen was subsequently cut or tumbled by humans.

Uses & applications

Used as an ornamental and lapidary stone, in cabochons, beads, carvings, and mineral collections; it has little industrial value compared with ordinary quartz.

Geological facts

The dark color can fade with prolonged heating or intense light, and some very dark commercial material may be irradiated. It often resembles dark glass but is harder and lacks glass’s uniform appearance.

Field identification & locations

Likely quartz if it scratches ordinary glass, shows curved fracture surfaces, and does not show bubbles or perfectly uniform glassy texture. Common sources include Brazil, Madagascar, Switzerland, the United States, and Scotland.