mineral

Smoky quartz

Quartz, silicon dioxide (SiO₂), smoky variety

AI-generated identification · may be incorrect

Mohs hardness 7; translucent brown to gray-brown color, vitreous luster, and conchoidal fracture. It has a trigonal crystal structure and typically lacks cleavage; the rough edges and internal fractures are consistent with quartz.

Identified August 28, 2026More mineral →

Explore Smoky quartz 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

Forms in silica-rich hydrothermal veins, pegmatites, and cavities of igneous rocks, commonly gaining its smoky color from natural irradiation of aluminum-bearing quartz. Specimen age depends on its host rock, ranging from Paleozoic to recent geological settings.

Uses & applications

Used as a lapidary stone, ornamental material, and collector mineral; transparent, well-formed crystals may be used in jewelry. This rough piece has modest commercial value.

Geological facts

Smoky quartz is the national gemstone of Scotland and can occur as nearly black “morion.” Color may fade with heating or prolonged sunlight exposure.

Field identification & locations

Common in granite pegmatites and hydrothermal deposits worldwide, especially Brazil, the United States, Switzerland, and Madagascar. Confirm with hardness—quartz scratches ordinary glass—and its glassy luster; the image could also represent brown chalcedony or iron-stained quartz.