mineral

Smoky Quartz

Crystalline Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Grayish-brown to brownish-black; Luster: Vitreous; Crystal system: Hexagonal/Trigonal; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Grayish-brown to brownish-black
Luster: Vitreous

Identified June 2, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7 on Mohs scale; Color: Grayish-brown to brownish-black; Luster: Vitreous; Crystal system: Hexagonal/Trigonal; Specific Gravity: 2.65

Formation & geological history

Formed in intrusive igneous rocks like granite and metamorphic rocks. The smoky color is caused by natural radiation from surrounding rocks activating aluminum impurities within the crystal structure.

Uses & applications

Used extensively in jewelry (faceted gemstones, beads), ornamental carvings, and by collectors. Metaphysically valued for grounding and energy cleansing.

Geological facts

Unlike many other brown gemstones, smoky quartz is one of the few that occurs naturally in such large, dark crystals. It was historically used in China for the earliest known sunglasses during the 12th century.

Field identification & locations

Identify by its transparency or translucency, smoky color, and its ability to scratch glass but not topaz. Primarily found in Brazil, Madagascar, and the Swiss Alps.