mineral

Smoky quartz (likely rough or tumbled fragment)

Quartz, silicon dioxide (SiO₂), brown variety colored by irradiation and trace aluminum

AI-generated identification · may be incorrect

Typically Mohs hardness 7, brown to gray-brown, vitreous luster, translucent to transparent, with a hexagonal crystal structure and indistinct cleavage; conchoidal fracture and specific gravity about 2.65. The pictured piece appears dark brown, translucent, and naturally fractured or lightly polished.

Identified August 17, 2026More mineral →

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Physical properties

Formation & geological history

Forms in silica-rich igneous and hydrothermal environments, especially granite pegmatites and alpine veins; specimens range from Precambrian to recent geological ages. Common localities include Brazil, Switzerland, Madagascar, the United States, and Scotland.

Uses & applications

Used as a lapidary and jewelry stone, ornamental material, and mineral specimen; clear smoky quartz can be faceted, while fractured pieces are commonly collected.

Geological facts

Its color is generally produced by natural radiation acting on trace aluminum impurities; heating can fade or alter the color. Exact identification from the photograph is somewhat limited because very dark brown obsidian or quartz-rich material can look similar.

Field identification & locations

Look for glassy luster, conchoidal fracture, translucency, and hardness sufficient to scratch ordinary glass; quartz lacks obvious cleavage. Estimated value is about $2–$20 for a small common fragment, or $25–$200+ for attractive, well-formed crystals.