mineral

Tumbled smoky quartz

Quartz (SiO₂), smoky variety

AI-generated identification · may be incorrect

Likely a small polished or naturally worn quartz fragment, translucent brown-gray with vitreous luster. Mohs hardness 7; hexagonal crystal structure, no cleavage, conchoidal fracture; specific gravity about 2.65.

Identified August 8, 2026More mineral →

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Physical properties

Formation & geological history

Smoky quartz forms in silica-rich igneous and hydrothermal veins, where natural irradiation colors clear quartz brown. Crystals range from ancient Precambrian specimens to much younger hydrothermal deposits.

Uses & applications

Used as an ornamental and lapidary stone, in jewelry, carvings, and mineral collections. Common small tumbled pieces generally have modest commercial value.

Geological facts

The dark color is caused mainly by irradiation-induced color centers associated with trace aluminum. Strongly colored transparent crystals are more valuable than opaque or heavily fractured material.

Field identification & locations

Common sources include Brazil, Madagascar, Switzerland, the United States, and Scotland. Confirm with hardness testing—quartz scratches ordinary glass—while avoiding destructive tests on a collectible piece.