mineral

Polished smoky quartz pebble

Quartz (SiO₂), likely smoky quartz or brown chalcedony

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent gray-brown color, vitreous to waxy luster, conchoidal fracture, and no visible cleavage. The smooth rounded form indicates tumbling and polishing; internal cloudy bands may reflect inclusions or chalcedonic texture.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Quartz forms in silica-rich igneous, hydrothermal, and sedimentary environments; smoky coloration commonly results from natural irradiation affecting trace aluminum. Quartz is widespread and ranges from Precambrian to recent deposits.

Uses & applications

Used as a lapidary stone, cabochon, meditation/collecting specimen, and occasionally jewelry. Common polished pieces typically have modest commercial value.

Geological facts

The photograph cannot reliably distinguish smoky quartz from brown agate, jasper, or other quartz varieties without testing. Glass can look similar but is usually softer or lacks natural internal texture.

Field identification & locations

Commonly found in Brazil, Madagascar, the United States, Uruguay, and worldwide quartz deposits. Confirm with a scratch test against glass, 10× magnification, and specific-gravity or refractive-index testing; avoid scratching the specimen if valuable.